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 Books could be out of date as far as equipment is concerned, and an internet forum could cause confusion by the different opinions expressed.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.