Are Rotating Powerheads Any Good?

There are several important factors that should be present if a marine aquarium is to be a success. In both fish only and reef aquariums seawater movement is one of them.

One reason for the importance of movement is oxygen intake, if it is adequate the seawater will constantly reach air/water interfaces, in particular the display aquarium surface, where gas exchange can take place. Another reason is that it assists corals obtain food and rid themselves of mucus.

There are several ways of providing adequate movement, some advanced and some ‘basic’. It is likely that many (most?) aquarists use ‘basic’ equipment, namely powerheads. These devices are available in more than one type, though they are all basically an electric motor made seawater safe by encapsulating it in resin, the motor drives an impellor, and there is a seawater intake and outlet. The powerheads could be narrow outlet or wide (‘soft’) outlet types. The wide outlet ones are able to move large quantities of seawater but because they push out the seawater on a wide front the impact is soft and not harmful to corals, particularly if there are two in opposition or they are timed. Narrow outlet powerheads pump a much thinner stream of seawater which is very linear and can damage fairly close corals because of the force.

Random and chaotic seawater movement is the aim and this is often obtained by placing powerheads in opposition to each other and also ‘bouncing’ the outlets off the glass. This should result in the desired seawater flow once a bit of trial and error with powerhead positioning has been completed.

With the narrow outlet powerheads there is a further option and this is to use the generated flow of the seawater to drive a mobile directional outlet. This type of outlet can be bought as an ‘add on’ or alternatively a powerhead obtained which has the required outlet fitted. What happens is that the flow of the seawater from the powerhead causes the outlet to swivel from side to side in an arc. The movement of the outlet is not particularly fast and when the end of the arc is reached the direction is reversed. Another method is an outlet that spins, the seawater acting something like jet propulsion driving it round.

This idea has merits. The seawater flow is automatically being re-directed continuously which is good and in itself is going to create varying currents in the aquarium. If there are two powerheads present, for example, and each has a rotation ability then continuously varying seawater flow will be generated at each end of the aquarium. In addition, from time to time the outlets will come into direct opposition to each other and create more random currents.

Of course there have to be disadvantages! First of all, the rotation is driven by the outlet from the powerhead which detracts from the strength of the flow, though this could be compensated for by the powerhead strength itself. The rotation mechanism is submerged in seawater and there is the possibility (probability?) that the rotation will slow down or cease because of calcareous build up. Also, the seawater from the outlet is still linear even though it is rotating, though it would hit a coral that is in the way X number of times per minute rather than continuously. Standard powerheads require their outlet strength checking from time to time and in addition the rotating powerhead needs checking to ensure the rotation mechanism is operating correctly, meaning there is a small addition to routine maintenance checks.

Rotating powerheads are a useful idea and I have nothing against them. However, and this is purely personal, I prefer standard powerheads that have been correctly sized and placed. Better in a suitable aquarium would be wide or ‘soft’ outlet powerheads in opposition, or timed.

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How Do UV Sterilizers Work?

There are all sorts of equipment that could be used to assist maintain the aquarium, each designed for a specific purpose. Some of this equipment is essential and there is no debate about its need, for example heaters. Other equipment could be cause for debate.

A piece of equipment that does cause some debate about its use and necessity is the UV sterilizer. UV stands for ultraviolet. Some aquarists use it, some do not. It is often seen in the LFS (local fish shop) as they try and combat the danger of disease.

UV light is dangerous to the human eye and is also dangerous to certain tiny life forms that could find their way into the marine aquarium. With a UV sterilizer attached, the aquarist hopes that any disease organism will be prevented from becoming a serious nuisance. The UV sterilizer is an aid to disease prevention, not a total answer.

The sterilizer is usually an elongated tube shape. Basically there is an outer casing, an inner glass casing, then the bulb. Ordinary glass cannot be used as it absorbs nearly all the UV radiation, therefore quartz glass is used which is of the type that prevents UV radiation below 220nm (nanometers) from passing through. (This is because of the problem of ozone generation, ozone is produced below 200nm.) The wavelength produced is stated to be 254nm. UV penetrates seawater to about ¾” (circa 2cm); therefore the seawater flow past the UV bulb is restricted to this depth.

Seawater flow rate is important. Too fast a rate and organisms will not be exposed for long enough. Therefore it is very important to check the manufacturer’s recommendations for the flow rate to ensure a suitable pump is connected. In addition, the bulb has a finite life and again the manufacturer should give information. Once ‘time is up’ the bulb must be changed.

Proper exposure to UV will kill or damage free floating algae, bacteria, protozoans etc. Pond keepers make use of UV as well as marine hobbyists.

A downside of using UV with a marine aquarium is that anything that is small and is irradiated will be affected. There isn’t any differentiation between good and bad. The bio-filter is an absolute requirement for the health of the aquarium and worry might be caused as the bio-filtration is performed by bacteria. However, these bacteria are not harmed as they are resident within one place, either live rock¸ a canister filter or similar. They are not exposed to radiation. If there is plankton in the aquarium then these could be exposed. However the plankton count in an aquarium is usually either very low or non-existent. If there is a presence they are likely to be damaged by impellors.

The major use for UV with a marine aquarium is assisting with the prevention of disease organisms and assisting with the treatment of the same if disease appears.

Major problems that could strike are caused by single celled parasites, which attach to fish and, if untreated, are likely to reach such numbers that fish death occurs. Fortunately there is a chink in the parasite’s armour, and this is that they have a free swimming stage, when they are known as tomites. It is when they are in this stage that exposure to UV is effective.

The parasites attach to the fish and after a fairly short period drop off. They fall to the bottom and divide into more parasites. They then return to the seawater column looking for fish to infect. Then the cycle begins again. When they are free swimming the UV can severely damage them. As I understand it their DNA ‘memory’ is disrupted, which means that when they reach the divisive stage, put simply they can’t – so no more parasite production.

It sounds like the complete answer to some disease problems but unfortunately it isn’t. For the UV to inflict damage the parasite has obviously to be exposed to the light. Can that be guaranteed in an aquarium? Unfortunately not, just consider the reef or aquascape with all the caves, nooks and crannies, also the sand bed. Then there are the areas in the aquarium usually low down or in corners where seawater flow is low. The seawater flow close to the intake of the UV sterilizer could cause parasites to get sucked in, but there are more likely than not to be those that don’t in other aquarium areas. One or two parasites could restart the whole process.

A UV sterilizer, properly set up, is a good aid for disease prevention and treatment. It is not an answer in itself and cannot be relied upon as such. The main defences must always be in place: careful fish selection, careful introduction, appropriate feeding and high quality overall aquarium husbandry.

(Reference: Baensch Marine Atlas. Helmut Debelius & Hans A. Baensch)

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Watch The Heat From That Metal Halide

Metal halide lighting is very popular with reef keepers, particularly those who keep hard (SPS) corals. This is because it is a very powerful light that can penetrate deep into the aquarium provided that the bulb wattage has been correctly selected. Metal halide is likely to be superceded before too long by LED arrays, but at the moment metal halide is the most popular for the reef.

Even though metal halide is so good at lighting reefs there are disadvantages. There are two major ones, the first being that metal halides are electricity hungry and will add significantly to the aquarium energy cost. The second is that they generate a lot of heat. It is this second disadvantage that is being considered.

The lighting has to be hung well above the seawater level and this is because should the protective glass or bulb be splashed it could crack as it is so hot. It needs to be remembered that if the glass is to be wiped over with a damp cloth it needs to cool down first.

We nearly all like sitting in a favourite spot in the sun, feeling the warmth. Metal halides bulbs are a little like the sun in that they radiate considerable heat and unfortunately this could cause trouble. Many reef keepers use cooling apparatus to keep the temperature of the seawater under control though this for most is only in summer. This apparatus could be fans in the lighting hood, a pedestal fan alongside the aquarium, a ‘chiller’ (electric seawater cooler), or perhaps a combination. Stability of seawater parameters is important and this includes temperature. If the temperature climbs too high livestock welfare is in jeopardy. If the temperature is noted to be climbing much too high then the first action is to turn off the metal halides until cooling equipment can be used. The aquarium shouldn’t be plunged suddenly into total gloom, so the blue (actinic) fluorescents can be left on.

There is another danger from metal halide heat as well, and I wasn’t aware of this until recently. There are aquarists who use acrylic aquariums and these aquariums, like glass ones, have stress bars built in across the top. It is reported that the major failure with acrylic aquariums is where a metal halide bulb is directly above a stress bar. The heat softens the acrylic which then stretches under the outward pressure of the seawater and splits or worse could occur.

So if it is possible to move the bulb away from the stress bar this should be done. If the metal halide is then off centre this could be all right, check the light coverage. The guideline is that a metal halide bulb at the correct height above the aquarium should light three feet of aquarium length.

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The Basic Kit For A Marine Aquarium Part Two – Reef

Part one dealt with a fish only aquarium and much of what is said in that text also applies to a reef system. The text therefore repeats itself in several places.

However, the reef aquarium has demands that are additional to the requirements of a fish only aquarium. This is not to say that a successful reef aquarium is much more difficult to obtain, it isn’t. However, the aquarist must pay attention to the additional needs. The reef aquarium demands are different, not difficult.

Despite the number of modern books available and information on the internet confusion continues to arise with a newcomer. This confusion is sometimes caused by the book and/or the internet. Books could be out of date as far as equipment is concerned, and an internet forum could cause confusion by the different opinions expressed.

Another area of confusion and often ‘overspend’ is the LFS (local fish shop). Some are very good and will ascertain the level of experience of the aquarist, and what he/she is aiming for. However, there are those that don’t and these are the ones that cause trouble. The LFS, good or poor as far as the beginner is concerned, is there to make money. If they don’t make money they won’t be there much longer. So the beginner is told they must have this, they must have that, this will be all right, that should do. Unfortunately this all adds up to a fair amount of money and ‘should do’ actually is not good enough.

The Aquarium. (The glass or acrylic box it all goes in.)

First of all (having obtained the agreement of the wife/husband/partner – let’s play safe) a check of available space should be made. The position of the aquarium must be close to an electrical outlet and the outlet must be accessible when the aquarium is in position, it can be just to one side or just behind (not in the middle). Also and important, check the strength of the floor to ensure it is strong enough. Concrete floors are fine and so are most suspended floors, but nevertheless check. An aquarium full of seawater and rocks is very heavy.

Once the available space is known then this is not necessarily the size of the aquarium that will be obtained. It is necessary to consider the overall cost and future running costs before making the commitment.

The Lights. (So fish can see and be seen – but there is more.)

Lighting for the reef aquarium is an area where confusion understandably could arise. Basically it is simple as will be seen.

Reef aquariums house corals. These could be of the soft or hard varieties, and there is one thing they have in common. Most of the corals kept in home aquariums contain zooxanthellae. Zooxanthellae are simply single celled algae which are embedded in the flesh of the corals. The alga is very important to the corals as 80% or more of the corals nutritional needs are provided by it. It is the alga that gives the coral its colour.

Algae have a particular need in order to thrive and that is light. Light permits it to photosynthesize, with insufficient light the algae will suffer and so will the coral. So the aquarist has to provide adequate lighting.

Adequate lighting will have two properties: the first is spectrum and the second is power. Spectrum simply means, as far as we are concerned, colour. Zooxanthellae respond well to blue light and manufacturers produce bulbs and tubes that will reproduce this. The light is in a fairly restricted range and is referred to as ‘actinic’. (Using these lights has the secondary benefit of causing some corals to look really amazing.) In addition to blue lighting, a cool white light is used often referred to as ‘marine white’. This is a mixture of colours, including blue, but to our eyes it appears white. So reef aquariums usually employ a mixture of light sources as described.

Light is measured on the Kelvin (K) scale. Light could be 10000K, 14000K up to about 20000K. The higher the number the more blue, or cold, the light appears. A reasonable metal halide bulb to use with a reef system would be 10000K or 14000K. When used with fluorescent blue (actinic) tubes a good effect is achieved.

The light of course has to reach the zooxanthellae to be of any use, and it has to get there with sufficient brightness. Light is rapidly weakened by seawater. The colours disappear individually; the first to go is red in the first few feet though blue penetrates very deeply. What this means for the aquarist is that the lighting over the aquarium has to have sufficient power to penetrate the seawater sufficiently. This power is measured in watts (W) and manufacturers provide lighting of different power outputs.

There are two main lighting types with a third becoming likely to supercede the first. The first is metal halide bulbs. The second is fluorescent tubes. The third is LED lighting. It is not intended to go through them all technically but a basic description follows.

Metal halide bulbs are currently used a great deal on reef aquariums. As stated they are bulbs which are housed in a reflective canopy. They produce a pinpoint and very bright light. The bulbs can be obtained in various spectrum and power variations. Unfortunately there are disadvantages in their use: they are expensive to run, in other words they are electricity hungry, the bulbs need replacing periodically, and they are capable of heating up the seawater. Though there is some argument over the necessity, many aquarists use metal halide bulbs together with two fluorescent blue (actinic) tubes.

Fluorescent tubes have been around for a long time. There is a choice in their length so various size aquariums can be accommodated. Manufacturers produce different spectrum outputs so that a mix can be used if desired. If they are to be used they should be fitted with reflectors. Using the colours described earlier, a mix of blue (actinic) and marine white is desirable. As many tubes fitted with reflectors as will fit should be used. If an even number of tubes will fit, have half blue and half white intermixed. If the number fitted is odd, the odd one should be white. T5 tubes are recommended, these are driven by electronic ballasts. The disadvantages of fluorescent tubes are that they must be changed periodically and they do not have as much penetrative power as metal halide bulbs.

LED lighting is becoming more available and the combined output of the LED’s is suitable for a reef. The lighting can be obtained as a canopy array containing many LED’s or as tubes containing much fewer LED’s. The latter are available with different colour outputs, the most useful probably being blue and white. If using the LED ‘tubes’ it is best to fit as many as possible over the aquarium, again with a mixture of blue and white as described above. The canopy array is a large over-tank light source containing many blue and white LED’s. There isn’t a requirement for any additional lighting. It is important to have an array large enough to light the full aquarium, as far as possible. The advantages with LED lights are that the lights last for years without the need for replacement, they do not heat the seawater, they can sometimes be controlled often by built in timers, and they are reasonably cheap to run. The disadvantage, at least at the moment, is that they are expensive.

So how is a lighting system chosen? No-one wants to over-light their aquarium as money will be wasted on electricity. Nevertheless, as said, the lighting must be adequate. Spectrum is quite easy to decide, all corals that require light will benefit from the same spectrum – blue and white.

Power is the problem usually. Power is measured in watts (W) and there is an array of power outputs never mind lighting types.

The first thing to consider is what corals are going to be kept, soft or hard? Most home aquariums are not deeper than 2 ft and it is the depth that is important.

If soft corals are to be kept, then fitting T5 fluorescent tubes as described should be adequate. Consider LED’s but as said they are expensive. Metal halide bulbs will probably be overkill.

If hard corals (SPS, which stands for short polyp stony) are to be kept, then again T5 fluorescent tubes could be adequate. (Note the change from ‘should’ to ‘could’.) Observation of the corals will be required to ensure they indicate growth and health – those at the top areas of the reef should be fine, it is the ones lower down that could be receiving less light. Consider an LED canopy array, but as said they are expensive. It could be desirable to ensure adequate lighting by employing metal halide bulbs along with two blue (actinic) fluorescent tubes in reflectors. The guideline for metal halide bulbs is that one bulb will light three feet of aquarium. So a six foot aquarium would need two bulbs.

Now for power on which light penetration into seawater depends. The guidelines for metal halide bulbs are: for a 24″ deep aquarium 400W, for an 18″ deep aquarium 250W, and for a 12″ deep aquarium 150W. (Note – 1″ is circa 2.5cm.)

The guidelines given are to enable proper light penetration generally to the bottom of the aquarium. So position of corals on the reef will dictate to a great extent the bulb power required. If the aquarium is 24″ deep and the hard corals are in the top 12″ then a 400W bulb could be downsized, subject to what is to be kept in the lower part of the aquarium.

It is a good idea when setting up lighting to include two electric timers, as they can be used to provide a more natural ‘dawn and dusk’ effect. The blue lights come on first, then half an hour later the main lights, be they metal halide or white fluorescent tubes. At the end of the day the white lights go off, followed half an hour later by the blue lights. The need for electric controllers may not apply to LED systems as sometimes these are included.

The Bio-Filter. (The bacteria factory providing life support.)

The bio-filter (biological filter) is absolutely essential. If one is not present, or is inadequate, the livestock will suffer or die.

There are two ways of providing bio-filtration (there are more than two but two will be looked at). These are first live rock and second canister filters. It is necessary to roughly know the total gallonage of the aquarium. The gallonage is easily calculated by using the formula Length x Breadth x Height, the answer divided by 231 equals US gallons. Allow for a 1″ airspace at the top of the aquarium and 2″ at the bottom for a decorative sand bed.

Live rock is a natural product which is bought ‘cured’ from a LFS. ‘Cured’ means that any potential die-off of organisms has occurred and the rock is ready for introduction to the aquarium. The rock contains bacteria that deal with the production of toxic substances in the seawater; this process is called The Nitrogen Cycle. The usual guideline for the amount of live rock is 1½ lbs per gallon of seawater. This guideline suffers from the fact that different live rock has different weights, so the supplier should advise the necessary amount required for the type being sold.

The live rock also acts as a natural décor for the aquarium interior.

A canister filter is a man-made device where seawater moves through a cylinder filled with bio-media. In and on the bio-media are the bacteria, once the bacterial culture has been established. The seawater flow is powered by an electric motor. These devices are fully capable of maintaining a bio-filter. A check should be made that the device is capable of handling the gallonage of the aquarium; the manufacturer’s information should provide this.

Of the two bio-filtration methods live rock is the one recommended particularly for a reef system. The live rock in addition to its filtration capabilities provides the material for a natural looking reef, and hopefully some wild life that has survived the curing process could appear. Another reason for using live rock is that within reason it can deal with nitrate. With a canister filter the Nitrogen Cycle stops after the production of nitrate. This does not mean that canister filters cannot be used as nitrate is controlled easily enough.

If a canister filter is to be used then the aquarist will need to purchase decorative rock to aquascape the aquarium. This will not be live rock of course but dead inert rock. ‘Inert’ means that the rock is known to be totally safe in seawater; nothing will leach out that is detrimental. There isn’t any control on the amount of inert rock used; it is up to the aquarist to create the aquascape desired. However, if fish are to be kept (they need to be reef safe) then consideration needs to be given to swimming space. Some fish need more space than others.

Powerheads. (These provide seawater movement.)

Seawater movement in an aquarium is required so that oxygen can be replenished and the general environment remains healthy. In addition, the movement helps corals rid themselves of mucus and detritus and brings food to them. Though there are several ways to provide seawater movement, powerheads are much used and fully acceptable. Here we deal with basic narrow outlet types, though there are wide outlet types available. Properly situated, narrow outlet powerheads are acceptable.

Usually at least two powerheads are used as this permits chaotic and random seawater flow to be created. One powerhead could go in one rear corner of the aquarium and the second in the other. The outlets, which generate linear flow, are directed at more or less the same place on the front glass. This means that the two flows interfere with each other as well as ‘bounce’ off the front glass and many swirls and multi-directional flows are created. It is usually necessary to experiment a little with the best positions for the powerheads, but it isn’t difficult. The movement of corals or bits of detritus in the seawater indicates the flow patterns. The outlet from the powerheads must be positioned so that strong linear flow from them does not strike a coral.

The guideline for seawater movement in a reef system depends on what is being kept. If it is a soft coral reef then the seawater gallonage in the aquarium should be moved around 10 times per hour. If the corals to be kept are hard (SPS) types then the seawater should move around 20+ times per hour. Note that these are guidelines and not rules – it is not critical, the volume moved does not have to be completely accurate.

For example using the guidelines, in a 50 gallon aquarium containing soft corals the total seawater movement per hour required is 500. Therefore each powerhead would need to move 250 gallons per hour. In an SPS system, the total seawater movement required is 1000 gallons, so each powerhead would need to move 500 gallons per hour. There isn’t any requirement to have two powerheads, many aquarists use three, four or more depending on the size of the aquarium and the amount of seawater that has to be moved. The required power of the powerheads is achieved by dividing the number of powerheads into the amount of seawater that needs moving. The seawater currents created should be as described.

Decorative Sand Bed. (It looks good.)

There isn’t a need for a decorative sand bed. It hasn’t a function except to make the aquarium look more natural and cover up the bare glass bottom. Decorative sand at the base of a reef does look attractive.

If a decorative sand bed is incorporated, then there are things to consider. First, it should be constructed of coarse coral sand, as hopefully this will not move around too much in the seawater currents and dirt will not penetrate too deeply too quickly. It is likely the sand will move and hopefully it will end up in decorative swirls and ripples similar to sand on a beach adding to the attraction. Second, rocks whether they are the live or inert variety should not rest on the sand. This should avoid rock falls and sand compression. So the rocks are in first then the sand. Last, the sand should be 1″ to 2″ deep. This depth will assist with cleaning by stirring when it becomes necessary to keep the bed looking its best.

The Protein Skimmer. (Not last and not least.)

After the bio-filter the protein skimmer is, perhaps arguably, the most necessary device. The protein skimmer is a great aid to the maintenance of high quality seawater. In an aquarium organic substances are produced which are generally termed Dissolved Organic Matter (DOM). This is mainly undesirable.

The protein skimmer removes much of this DOM. All types of skimmer work on the same basis: seawater flows through a chamber where very high numbers of tiny air bubbles are present. The DOM is attracted to the air/water interface and ‘adheres’ to the bubbles. The bubbles rise and fall into a collection cup and periodically the collection cup is emptied.

Most skimmers used nowadays are electrically driven and employ a ‘venturi’ device to draw air in. There are two types, stand alone and hang-on. With the basic aquarium set-up, where a sump is not in use (a sump is an additional tank under the display aquarium), the hang-on type is most useful.

Manufacturers nowadays are perhaps more accurate in their claims for the performance of their products, but nevertheless the following guideline applies: obtain a skimmer that is stated to be capable of handling around twice the gallonage of the aquarium. It is unlikely that a skimmer will be obtained that is stated to handle the aquarium gallonage exactly, but one could be close, so at least choose the skimmer higher up the scale, not one lower down.

The skimmer is said to be the number one ‘poor buy’. This means that many aquarists setting up a system try to economise on this item, only to discover the inadequacy of the device and their mistake later, resulting in another purchase and unnecessary expense.

Heaters. (Got to keep the coral reef cosy!)

The corals and fish that are to be kept are from the warm seas of the wild reefs so it follows the aquarium seawater needs to be warm, between 75 and 80 deg F. Many aquarists choose 77 deg F.

The method of keeping the seawater warm is to use a device called a heater/stat. This is like a long fairly thin tube, the more powerful the heater the longer the tube. The heater is turned on and off by the ‘stat (thermostat).

It is best to have two heaters. Though they are quite reliable nowadays, failure is not unknown and it is often the ‘stat that is the trouble. It either sticks in the ‘on’ or ‘off’ position, usually the ‘on’. This means that the heater continues to apply heat even when the seawater is at or above the required temperature. If there was one heater it would heat the seawater excessively too quickly with dangerous consequences for the livestock. With two heater/stats this can be avoided to a considerable extent as each heater/stat is rated at half the power required. Therefore a safeguard is provided.

The guideline for selecting the heating requirement of the aquarium is: if the aquarium is in a heated room allow 2 watts per gallon of seawater. If the aquarium is in an unheated room allow 4 watts per gallon.

So, with 50 gallons of seawater and using two heater/stats, in a heated room the power requirement in watts (W) of each heater/stat will be 50 watts. In an unheated room the heater/stats would be rated at 100 watts apiece.

Calcium Provision. (Let the corals grow.)

Calcium is used by corals in their growth processes, mainly by hard corals that can make quite a demand, and also by soft corals which have ‘spicules’ (stiffeners) in their flesh. Other livestock such as snails and shrimps also have a need. So it follows that calcium must be present in sufficient quantity.

The guideline for calcium in a reef aquarium is 400+ ppm (parts per million). Incidentally, ppm is considered the same as mg/l. This amount is fine for soft coral aquariums though a higher level is better, say around 420 ppm. Aquarists who have a hard (SPS) reef often maintain higher levels than this, 450 or even 480 ppm.

So how is this calcium supplied? Routine seawater changes help but are not usually sufficient. It depends on the demand and the size of the aquarium. A small or medium soft coral reef could use supplements to provide calcium, and probably the same for a small SPS reef. The answer with these is to use a supplement and judge how much is being used and if it is effective and not too expensive. If it is ineffective or too expensive then the following could apply.

A medium to large well stocked hard coral (SPS) reef will make a considerable demand for calcium. It is unlikely that supplementation with a commercial product will be cost effective. Therefore a device for providing the calcium has to be used. There is more than one way of providing calcium but here the calcium reactor will be considered.

A calcium reactor is a device that passes seawater through a media filled chamber that has a low pH. The media is rich in calcium. The pH is lowered in the chamber by injecting controlled amounts of carbon dioxide. The media slowly dissolves and is passed into the aquarium. The device needs adjustment for seawater flow rate and for the injection speed of the carbon dioxide.

Once the aquarist is aware of the calcium demand of the corals then the reactor can be adjusted to meet it. New media is required from time to time.

As experience grows the aquarist could find supplementation other than calcium is also required, but calcium is the only one that will be looked at here.

Seawater Test Kits. (Seawater quality is so important.)

In order to keep a high quality marine environment it is very necessary to routinely test the seawater in addition to doing routine seawater changes. The test kits needed are easily obtainable, not excessively expensive and easy to use.

The first requirement is a hydrometer. This is usually a one-time buy as it is re-usable. The hydrometer is a device that indicates the specific gravity (SG) of the seawater. In a reef system the SG should be 1.024 or 1.025 and stable.

Next are the tests that look for undesirables in the seawater. The three of interest are ammonia (a deadly toxin), nitrite (a toxin nearly as deadly), and nitrate (which is nowhere near as bad but detrimental at too high a level). These kits carry out a finite number of tests and a new kit will be required.

Next a test kit for pH is needed. Seawater is alkaline and the pH test checks this. The reading should be between 8.0 and 8.4. Again the kit has a finite number of tests and a replacement will eventually be needed.

There is a saying that nothing should be put into the seawater that cannot be tested for. Well, calcium is being added and this needs to be checked. The levels required have already been discussed. This also is a kit that will need replacement in time.

There are other tests that could be made and the aquarist will learn of these as experience grows.

Dry Sea Salt. (Well, it is salty water!)

There are many different makes of dry sea salt available and this is a choice for the aquarist. The most salt will of course be used in the initial mix. Following that, routine seawater changes should be done weekly, and at least to start, 10% of the total gallonage should be changed.

A Reverse Osmosis Filter. (Makes good water.)

Though this is not an absolute necessity for the running of the basic aquarium, the advantages of using one means that it is highly recommended. This is because much tap water contains undesirables.

When tap water runs through a reverse osmosis (RO) filter, the usable fresh water that emerges is 95 to 98% pure. Any contaminants have been removed. The fresh water can be used with confidence with the dry sea salt.

The Cost. (Not the most exciting consideration.)

There are two costs to consider.

First, now that everything has been listed, that is, the aquarium and the necessary equipment, check prices at the LFS and on the internet. Note down those selected and add them up. The answer is the indicative cost of setting up the system.

Now list the electrical items. Find out the wattage (W) of each and write it down (the information should be on the packaging, the device, or the manufacturer’s information). Now add up the list of watts. This is the indicative total power requirement of the system.

However, not everything will be on all of the time, lights and heaters being an example. An allowance is made for these. To calculate the ongoing electrical cost, use the article on this site called ‘A New Aquarium – It’s Exciting But Check Running Costs’. The calculation is straightforward. Alternatively, use an online calculator; these are available on several marine forum sites.

If everything is acceptable, fine. If not, perhaps downsizing the aquarium would produce a positive outcome.

(Note : All of the above links are to the relevant category of Aqua Compare and open in a new window.)

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How Long Should You Leave Refugium Lights On For

Refugiums are becoming more and more popular nowadays as people are starting to realise the beneift that they can have upon the aquarium.

Refugiums, as the name states are a refuge for animals to live without fear of predation. It is also an area where macro algae can be grown to assist in the removal of nutrients from the water.

In a normal refugium macro algae is grown to assist in the removal of nitrate and phosphate. In the refugium may also be a scattering of sand, a deep sand bed or even a mud bed.

Macro algae normally will only remove nutrients when it is actively growing and for this to happen it requires a light source.

The best light source to use is lighting which is correct for the growth of plants – this is normally in the lower end of the kelvin scale.

In the display aquarium the lights are left on for between 8 and 12 hours however how long should the lights be left on above the refugium?

There are two answers to this question:

1. The lights are left on for a 24 hour period. With this method the algae is allowed to grow continuously and therefore remove more nutrients from the water column.
2. The lights are lit in what is termed reverse light cycle. What this means is that the lights above the refugium come on when the display aquarium lighting goes off and turn off when the display aquarium lighting comes on.

So what do I recommend and why?

Both options are valid options however I would recommend option 2.

The reason for this is that I like to follow nature. In nature the grass beds are not subject to lighting over a 24 hour period – the receive light when the sun is out!

I also believe that the algae needs a ‘rest’. It requires a lot of energy for the algae to grow and if it grows continuously then problems may occur. This is not something that has been scientifically proven but is something that I believe could happen. It also needs to be remembered that in the refugium other organisms also exist. There will be various types of organisms which, like most life would prefer a period of darkness. I read somewhere, unfortunately I cannot remember where, that in a refugium which was provided with darkness the population of organisms grew however if the lights were on continuously the population did not grow as fast.

There is another area which is important and both of the above methods provide this – pH stability. When the lights go out above the display aquarium there is normally a slight pH drop throughout the hours of darkness. If the refugium is lit throughout these hours of darkness then the pH drop may be countered. As with anything in this hobby stability is key and this is just another area where this stability can be maintained.

So in my opinion the refugium can be lit of a 24 hour period or it can be lit on a reverse cycle however if I was to choose then I would choose reverse cycle for the reasons listed above.

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Is There A ‘Best Size’ Aquarium To Start With

This is probably something which most beginners to this hobby ask themselves and it is a very valid question. A lot of people recommend that beginners start with the largest aquarium which they can both afford and fit into the designated area.

This is very good advice however it can also be confusing as well as off-putting. People sometimes look at the large aquariums as well as the required equipment, see the cost and then are put off.

The reason that a lot of people recommend a large aquarium to start with is due to the fact that it is easier to maintain water quality in an aquarium with more water volume. The way I explain this to people is in relation to a cup of coffee!

In a cup of coffee if you put a spoon full of sugar in there it will taste quite sweet however if the coffee was in a bucket then the coffee would not taste as sweet – if you could taste it at all.

The same is with an aquarium where nutrients such as nitrate and phosphate is the sugar.

So am I different or do I recommend the same.

Actually I am different – I recommend that people start with an aquarium size which is correct for them and their budget. If a new aquarists budget will not stretch to a 100 gallon aquarium then get a smaller one which is within budget. As long as it is known and understood that water quality is slightly harder to maintain in a smaller aquarium then why not get a smaller aquarium. It is better to get a smaller aquarium in my opinion than not get one at all.

If you are a beginner and do get a smaller aquarium then you will need to be vigilant with your feeding, your stocking levels, your water top ups as well as your water testing. As time progresses your self confidence and knowledge in the hobby will increase and this will make it easier.

Smaller aquariums in my opinion can actually be more interesting than the larger ones. In a small aquarium as you are not able to put as many corals, fish etc in as you can with the larger aquariums you can watch and study the aquarium inhabitants more closely. It also has the added benefit that the required equipment will not cost you as much.

As time progresses you may wish to invest in a larger aquarium or you may wish to downsize and go nano – or even pico however at the beginning, as said any aquarium is a ‘best size’ aquarium to start with as long as it is known that smaller aquariums require more careful management.

On a final note – when I say small aquarium I do not mean an aquarium which is very small – I would not recommend that any beginner start with an aquarium which has a water voluem which is less than 20 gallons.

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The Basic Kit For A Marine Aquarium Part One – Fish Only

Despite the number of modern books available and information on the internet confusion continues to arise with a newcomer. This confusion is sometimes caused by the book and/or the internet. Books could be out of date as far as equipment is concerned, and an internet forum could cause confusion by the different opinions expressed.

Another area of confusion and often ‘overspend’ is the LFS (local fish shop). Some are very good and will ascertain the level of experience of the aquarist, and what he/she is aiming for. However, there are those that don’t and these are the ones that cause trouble. The LFS, good or poor as far as the beginner is concerned, is there to make money. If they don’t make money they won’t be there much longer. So the beginner is told they must have this, they must have that, this will be all right, that should do. Unfortunately this all adds up to a fair amount of money and ‘should do’ actually is not good enough.

The Aquarium. (The glass or acrylic box it all goes in!)
First of all (having obtained the agreement of the wife/husband/partner – let’s play safe) a check of available space should be made. The position of the aquarium must be close to an electrical outlet and the outlet must be accessible when the aquarium is in position, it can be just to one side or just behind (but not in the middle). Also and important, check the strength of the floor to ensure it is strong enough. Concrete floors are fine and so are most suspended floors, but nevertheless check. An aquarium full of seawater and rocks is very heavy.

Once the available space is known then this is not necessarily the size of the aquarium that will be obtained. It is necessary to consider the overall cost and future running costs before making the commitment.

The Lights. (So the fish can see and be seen.)
On a fish only aquarium there aren’t any special requirements for lighting, but some care and forethought is nevertheless required. Two fluorescent tubes are normally sufficient and they should run the full length of the aquarium or as near as possible and be fitted with reflectors. One marine white tube and one blue (actinic) tube will enhance the colours of the fish. In addition these two tubes allow for a more natural ‘lights on and off’ sequence, by having the blue come on first followed ½ hour later by the white creates ‘dawn’, and in reverse creates ‘dusk’. This requires two electric timers.

The type of tubes doesn’t really matter, though T5 tubes which are driven by electronic ballasts are recommended.

The bio-filter. (The bacteria factory providing life support.)
The bio-filter (biological filter) is absolutely essential. If one is not present, or is inadequate, the livestock will suffer or die.

There are two ways of providing bio-filtration (there are more than two but two will be looked at). These are first live rock and second canister filters. It is necessary to roughly know the total gallonage of the aquarium. The gallonage is easily calculated by using the formula Length x Breadth x Height, the answer divided by 231 equals US gallons. Allow for a 1″ airspace at the top of the aquarium and 2″ at the bottom for a decorative sand bed.

Live rock is a natural product which is bought ‘cured’ from an LFS. ‘Cured’ means that any potential die-off of organisms has occurred and the rock is ready for introduction to the aquarium. The rock contains bacteria that deal with the production of toxic substances in the seawater; this process is called The Nitrogen Cycle. The usual quote for the amount of live rock is 2½ lbs per gallon. This guideline suffers from the fact that different live rock has different weights, so the supplier should advise the necessary amount required of the type being sold.

The live rock also acts as a natural décor for the aquarium interior.

A canister filter is a man-made device where seawater moves through a cylinder filled with bio-media. In and on the media are the bacteria. The seawater flow is powered by an electric motor. These devices are fully capable of maintaining a bio-filter. A check should be made that the device is capable of dealing with the gallonage of the aquarium; the manufacturer’s information should provide this.

Of the two bio-filtration methods live rock is the one recommended. This is because a product of the Nitrogen Cycle is nitrate. Within reason, live rock should deal with nitrate. The Nitrogen Cycle with a canister filter stops when nitrate is produced. This does not mean canister filters should not be used as nitrate can be controlled easily enough.

If a canister filter is to be used then the aquarist will need to purchase decorative rock for the aquarium aquascaping. This will not be live rock of course but dead inert rock. ‘Inert’ means that the rock is known to be totally safe in seawater; nothing will leach out that is detrimental. There isn’t a control on the amount used; it is up to the aquarist to create the aquascape desired. However, consideration of the fish is needed as they need swimming space, some more than others.

Powerheads. (These provide seawater movement.)
Seawater movement in an aquarium is required so that oxygen can be replenished and the general environment remains healthy. Though there are several ways to provide adequate seawater movement, powerheads are much used and fully acceptable. Here we deal with basic narrow outlet types, though there are also wide outlet types available. Narrow outlet types are perfectly adequate for a fish only system.

Usually at least two powerheads are used as this permits chaotic and random seawater flow to be created. One powerhead could go in one corner of the aquarium at the back, and the other powerhead in the other. The outlets, which generate linear flow, are directed at more or less the same place on the front glass. This means that the two flows interfere with one another and many swirls and multi-directional flows are created. It is usually necessary to experiment a little with the best positions for the powerheads to obtain the required effect, but it isn’t difficult.

The guideline for seawater movement is that the net gallonage should move 10 times per hour. So if two powerheads are being used each should be capable of moving half the gallonage 10 times per hour. For example, if the gallonage is 50, then the total required movement per hour is 500, so each powerhead needs to move 250 gallons. Note that this is a guideline not a rule – it is not critical.

Decorative Sand Bed. (It looks good.)
There isn’t a need for a decorative sand bed. It hasn’t a function except to make the aquarium look more natural, and cover up the bare glass bottom.

If a decorative sand bed is incorporated, then there are things to consider. First, it should be constructed of coarse coral sand, as this will not move around too much in the seawater currents and dirt will not penetrate too deeply too quickly. Second, rocks whether the live or inert variety should not rest on the sand. This should avoid rock falls and sand compression. So the rocks are first in then the sand. Last, the sand should be 1″ to 2″ deep. This depth will assist with cleaning by stirring when it becomes necessary to keep the bed looking at its best.

The Protein Skimmer. (Not last and not least.)
After the bio-filter the protein skimmer is, perhaps arguably, the most necessary device. The protein skimmer is a great aid to the maintenance of high quality seawater. In an aquarium organic substances are produced which are generally termed Dissolved Organic Matter (DOM). This is mainly undesirable.

The protein skimmer removes much of this DOM. All types of skimmer work on the same basis: seawater flows through a chamber where very high numbers of tiny air bubbles are present. The DOM is attracted to the air/water interface and ‘adheres’ to the bubbles. The bubbles rise and fall into a collection cup and periodically the collection cup is emptied.

Most skimmers used nowadays are electrically driven and use a ‘venturi’ device to draw air in. There are two types, stand alone and hang-on. With the basic aquarium set-up, where a sump (an additional tank under the display aquarium) is not used, the hang-on type is most useful.

Manufacturer’s are perhaps more accurate in their claims for the performance of their products nowadays, but nevertheless the following guideline applies: obtain a skimmer that is stated to be capable of handling around twice the gallonage of the aquarium. It is unlikely that a skimmer will be obtained that is stated to handle the aquarium gallonage exactly, so at least choose the skimmer higher up the scale, not one lower down.

The skimmer is said to be the number one ‘poor buy’. This means that many aquarists setting up a system try to economise on this item, only to discover the inadequacy of the device and their mistake later, resulting in another purchase and unnecessary expense.

Heaters. (Have to keep the fish cosy!)
The fish that will be kept are the colourful reef types, so the seawater needs to be kept warm, between 75 and 80 deg F. Many aquarists choose 77 deg F.

The method of keeping the seawater warm is to use a device called a heater/stat. This is like a long fairly thin tube, the more powerful the heater the longer the tube. The heater is turned on and off by the ‘stat (thermostat).

It is best to have two heaters. Though they are quite reliable nowadays, failure is not unknown and it is often the ‘stat that is the trouble. It either sticks in the ‘on’ or ‘off’ position, usually the ‘on’. This means that the heater continues to apply heat even when the seawater is at or above the required temperature. If there was one heater it would heat the seawater excessively too quickly with dangerous consequences for the fish. With two heater/stats this can be avoided to a considerable extent as each heater/stat is rated at half the power required. Therefore a safeguard is provided.

The guideline for selecting the heating requirement of the aquarium is: if the aquarium is in a heated room allow 2 watts per gallon of seawater. If the aquarium is in an unheated room allow 4 watts per gallon.

So, with 50 gallons of seawater and using two heater/stats, in a heated room the power requirement in watts (W) of each heater/stat will be 50 watts. In an unheated room the heater/stats would be rated at 100 watts apiece.

Seawater Test Kits. (Seawater quality is so important.)
In order to keep a high quality marine environment it is very necessary to routinely test the seawater, in addition to doing routine seawater changes. The test kits needed are easily available, not excessively expensive and easy to use.

The first requirement is a hydrometer. This is usually a one-time buy as it is re-usable. The hydrometer is a device that indicates the specific gravity (SG) of the seawater. In a fish only system the SG could be from 1.020 to 1.025. As there aren’t any corals present some aquarists keep the SG at 1.022 as it is thought there are some advantages for the fish at this level. However bear in mind that if there is a temptation to keep shrimps or the like (and the fish won’t eat them!) it’s best to keep the SG at 1.024 or 1.025.

Next are the tests that look for undesirables in the seawater. The three of interest are ammonia (a deadly toxin), nitrite (a toxin nearly as deadly), and nitrate (which is nowhere near as bad but at high levels undesirable). These all carry out a finite number of tests and a new kit will then be required.

Finally, a test for pH is needed. Seawater is alkaline and the pH test checks this. The pH reading should be between 8.0 and 8.4, and should also be stable. Again, the kit has a finite number of tests and a replacement will be required.

Dry Sea Salt. (Well, it is a marine aquarium!)
There are many different makes of dry sea salt available and this is a choice for the aquarist. The most salt will of course be used in the initial mix. Following that, routine seawater changes should be done weekly, and at least to start, 10% of the total gallonage should be changed.

A Reverse Osmosis Filter. (Makes good water.)
Though this is not a necessity for the basic aquarium, it is recommended. This is because much tap water contains undesirables.

When tap water runs through a reverse osmosis (RO) filter, the usable fresh water that emerges is 95 to 98% pure. Any contaminants have been removed. It can then be used with confidence with the dry sea salt.

The Cost. (Not the most exciting consideration.)
There are two costs to consider.

First, now that everything has been listed, that is, the aquarium and the necessary equipment, check prices at the LFS and on the internet. Note down those selected then add them up. The answer is the indicative cost of setting up the system.

Now list the electrical items. Find out the wattage (W) of each and write it down (the information should be on the packaging, the device, or the manufacturer’s information). Now add up the list of watts. This is the indicative total power requirement of the system.

However, not everything will be on all the time, lights and heaters being an example. An allowance is made for these. To calculate the ongoing electrical cost, use the article on this site called ‘A New Saltwater Aquarium – It’s Exciting But Check Running Costs’. The calculation is straightforward. Alternatively, use an online calculator; these are available on several marine forum sites.

If everything is acceptable, fine. If not, perhaps downsizing the aquarium would produce a positive outcome.

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