Water Movement In The Display Aquarium

Both the reef aquarium and fish only aquarium have certain demands that are very important. Top of the list is water quality, followed by lighting (for a reef anyway).

Water quality is of course measured, and for both types of aquarium the four basics are the same - ammonia, nitrite, nitrate and pH. With the reef the list is extended, taking into account for example alkalinity, calcium, magnesium etc.

Water quality is more than measurement however. Though a personal thing, I count water movement as part of quality. Water movement brings oxygen and food to corals, and helps removes dirt and mucus from them. It ensures fish have sufficient oxygen, and also makes them feel more ‘at home.‘ It also oxygenates a reef and assists in keeping it clean. The seawater is ‘clean’ and freshened in all parts of the aquarium. With good water movement the very important gas exchange is achieved - water is continually delivered to the surface to re-oxygenate.

Plenty has been written on this subject, and on this website, already about water movement and its creation. The methods are generally straightforward.

However, I suspect that many aquarists, particularly newcomers, look at water movement as circles. There’s the aquarium, and the guideline suggests water movement of, say, 10x the net gallonage per hour. Easy! Get a couple of powerheads which pump that amount of water, or somewhere near, and the job is done.

If suggestions have been understood, the powerheads are placed strategically to create chaotic and random water movement. Still well and good.

It is thinking ‘in circles’ though. Perhaps it would be better to say thinking ‘horizontally.’ No matter how carefully the powerheads have been placed the seawater cannot possibly reach all parts of the aquarium with good movement. All aquariums have quiet areas where corals that prefer calm can dwell.

So the aquarium is equipped with what seems to be sufficient power to move the water. Probably it is.

What about the ‘vertical’? No, I don’t actually mean pump water vertically in the aquarium, I mean deliver water low down from higher up. What about one additional powerhead that is in an accessible position but pumps water through a tube to, say, a spray bar behind the lower reef or even under it. There are different ways of delivery. All the powerhead needs is a sleeve on the intake (sponge or similar) to stop debris and that’s it. Maybe two powerheads would be required. Whatever.

The aquarist can then be more sure that water quality is high everywhere, with the benefits that can bring.

Advanced systems can use carefully designed closed loops, where the water outlets are positioned in strategic places to ensure fully advantageous delivery. The ‘ordinary’ aquarist need not go to these lengths unless really desired. The use of additional water movement devices, one or maybe two, will do a fairly similar job at a very reasonable cost.

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Tags: aquarium, Aquarium Water, reef-tank, saltwater-aquarium, Water Movement, Water Quality

Do You Have To Use Reverse Osmosis Water?

Reverse osmosis (R/O) water seems to pop up very regularly in questions and discussions. Some aquarists consider the R/O filter to be another piece of equipment that is not really necessary. There is quite a bit of confusion particularly with beginners, which is understandable when the whole spectrum of equipment and guidelines for keeping marine systems is considered.

The heading question can be answered straightaway - no, you don’t. If you’re lucky, and have a water source such as a well that provides water of high purity, or live in an area where tap water is of a really high standard and not polluted with nitrates, insecticides, metals, bacteria (I won’t go on) then the tank seawater mix could well be of high quality.

Some aquarists have tried using bottled spring water and found that the purity was in fact not as thought and/or the cost was prohibitive. Similarly, some have obtained a supply of distilled water from a chemist or other source and tried that. This proved to be an inefficient way of obtaining the amounts of seawater - multiple gallons - often required, plus the cost.

A few other aquarists have turned to Mother Nature, a fine choice provided the transportation and storage needs can be met, and an unpolluted source can be found.

So for the majority it is the household tap. The water from the mains tap is purified and regulations exist for the amounts of pollutants that are acceptable. Nitrate can be present in a surprisingly high amount, as can phosphate, plus the insecticides etc mentioned earlier.

The water from the tap at the very least should be tested for nitrates and phosphates before consideration is given to using it for a salt mix. If tests are not done then the aquarist is possibly preparing a potential home for nuisance algae, particularly if high power lighting is being used. Added to the pollutants in the tap water are the natural developments in the tank because of the natural processes of the livestock, and the results of potential overfeeding.

Personally, I find it difficult to follow the logic (should I say illogic) of not using R/O water. First, look at the expense the aquarist has accepted in preparing the aquarium system, having purchased lights, salt mix, test kits, a protein skimmer, canister filter, heater(s), circulation pumps, maybe a calcium reactor etc, and also of course the aquarium and stand. Then there is the internal decoration, such as live rock and maybe sand. The fish and corals haven’t been mentioned yet! Whether a fish only or reef system, it all represents a fair sized investment.

Over and over emphasis is placed on the need for high quality water. To this end, the dry salt mix that most aquarists use is manufactured to a high purity, lacking in such unwanted substances as nitrate and phosphate. Why add less than ideal water to it?

If there is a marine retailer close by, R/O water may be available to purchase by the gallon. Quite reasonably, the retailer has to make a profit. Moving the water in containers is not the easiest practice.

If the aquarist purchased an R/O filter then production of purified water would be straightforward and predictable demand easily met. The cost of the filter, particularly when the cost of other items of equipment is considered, is reasonable.

R/O water is generally 95 to 98% pure and the environment for the aquarium livestock would be enhanced, which is probably the most important point, and the possible appearance of undesirable headache algae would be reduced.

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Tags: Aquarium Maintenance, Aquarium Water, Care, Equipment, reverse-osmosis, Water Quality

How Does Reverse Osmosis Work?

As is so often repeated, high water quality is needed in a marine aquarium. Reef systems need higher quality than fish only, but both need to be maintained at the highest level possible. This is done by regular monitoring of water parameters.

A good way of enhancing water quality is by preparing the routine water change mix (and the initial fill) with a high grade salt mixed into reverse osmosis (R/O) water. This water is obtained by filtering tap water to remove undesirables therefore increasing the water quality in the first place.

R/O devices usually come in a unit containing three pods: there is a pre-filter to remove larger debris, a carbon filter to remove chlorine, and the R/O membrane itself. Some units have a fourth pod, which hold resins that take out any remaining undesirables. There isn’t any harm in having a fourth pod, they will increase the water cleanliness somewhat,  but they are not strictly necessary.

The R/O unit is connected to the mains supply in a convenient out of the way place (simple connectors are normally supplied with the device). The water is driven through the unit by the mains water pressure. They will not work if, say, supply water is gravity fed.

The water first meets the sediment pre-filter, which, as said, removes larger particles so that the next filter doesn’t clog.

Next in line is a carbon filter. This is very important as it removes chlorine. Chlorine is very detrimental to the R/O membrane.

The water now reaches the main point of the exercise, the R/O filter. This is a semi-permeable membrane. In other words, it will allow water to pass but not other unwanted substances. These substances could be insecticides, viruses, spores of fungi, metals, bacteria etc.

Finally, if the device has four pods, the final filter is a ’polishing’ unit. As said, it contains resins which will take out further pollution giving a slightly higher purity.

As has been said, the R/O membrane will only allow nearly pure water to pass through. Therefore there are two water outlets, one for the purified water (known as permeate) and one for the waste (known as concentrate). The aquarist runs the permeate outlet into a container for storage, and the concentrate to a convenient point for disposal.

R/O units come in various ’gallons per day’ outlets. The aquarist should purchase one that will provide sufficient water for the routine water change in a reasonable time. This will cover daily top-ups as well.

It is possible to connect an R/O unit to an automatic top-up device. This means when the water level falls it will be filled with purified water in the absence of the aquarist. For smaller systems, a daily top-up is usually sufficient.

It is very important to follow the manufacturer’s instructions when using the R/O device. The sediment pre-filter should be replaced or cleaned at the appropriate time. It is essential to replace the carbon filter when required, as failure to do so could allow chlorine to reach the R/O membrane and cause damage. This could allow impure water to pass through the membrane. This would mean obtaining a new membrane, which will be in the region of half the price of the entire unit.

R/O devices will provide 1/5th of pure water in relation to the water input. In other words, for every 5 parts of tap water, 1 part of purified water will be obtained. The purity on a three pod system is usually between 95 to 98%.

Using R/O water is highly recommended. As already stated, it sets the seawater quality at a high level from the start. From a logical point of view, manufacturer’s of dry salt mixes provide salt of a very high standard nowadays, with nothing undesirable present, such as nitrate and phosphate. Why pollute this salt with tap water?

If the aquarist has been using tap water to date, changing to R/O water is a good idea. Better, use it from the very start.

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Tags: aquarium, Aquarium Water, Equipment, reverse-osmosis, saltwater-aquarium, Water Quality

How To Ensure There Is Enough Oxygen In The Water

The marine aquarist does all sorts of water parameter checks to ensure the quality is high. A lot of money is spent on equipment and livestock. Once the livestock point is reached, occasionally problems will arise, particularly with fish in a fish only system. Though the aquarist may well be close to a nervous breakdown as all the water checks done do not cause any or much concern, the problem could be to do with oxygen.

Why should a fish only system be more likely to have a problem than a captive reef? In a captive reef it is usual to have less fish inches relative to seawater net gallonage than in a fish only system. Fish demand oxygen as do all living organisms (ok, there are some that derive their oxygen in less usual ways, but as far as I know everything needs oxygen). A heavy fish load will clearly demand a lot of oxygen.

The problem is rare. However, it does pop up now and again, usually with novice aquarists, and it is not that much a rarity. It often starts in the summer.

The aquarist, as said, has a heavy fish load, but is not concerned as they all seem fine. The bio-filter copes. Then along comes some warm weather. As would be expected, as the seawater heats up because of the increased temperature the heaters turn off. The temperature increase continues. Lighting is in use, and it is this that is heating the water, particularly metal halides. The aquarist does not have a chiller (seawater cooler) as they are expensive and the occasions the device could be needed are considered insufficient with regard to the cost.

The seawater contains 6 to 8 parts per million (ppm) oxygen in a well managed average tropical marine aquarium. Not a lot really. Warm seawater contains less than cold and this is a tropical aquarium.

It should be remembered that it is not only the fish that are using oxygen. There is the bio-filter. Unless this is a trickle filter, all the oxygen for the oxygen hungry bacteria is taken from the water. Oxygen supply could be getting near the edge.

If there is a sump with macro algae in it, then during daylight hours this will assist in oxygen replenishment. It has limits though. A properly functioning protein skimmer will also assist. Nevertheless, the situation is not as it should be.

Fish breathing rapidly, possibly combined with hanging around near the water surface, is a sign of oxygen depletion. So why has this happened?

First, it may be that the aquarium is overstocked with fish. This should never occur despite the temptations, as there is obviously an increased demand for oxygen, and the bio-filter has to work that much harder employing more bacteria - and as said these bacteria are oxygen hungry. Then the water temperature increased. This can happen to the best designed and cared for aquarium, and the first thing to do when a significant temperature rise is noted is to switch off the lighting, particularly metal halide. There are further ways of cooling the seawater that will not be gone into here.

Though problems can arise in any system, it is usually the aquarium that has been recently equipped and stocked by a novice that are struck. That’s the clue.

In a well designed marine aquarium system of any type consideration has been carefully given to water circulation to ensure maximum gas exchange, among other things. Water can be circulated in many ways but a commonly used example is the powerhead. Whatever device(s) are used for circulation, it is essential that the seawater moves sufficiently so that efficient air/water interface(s) occur. The usual major interface is the water surface, and it follows that if movement is adequate then the water will continually reach the surface before moving on and being replaced with more water - a continuous gas exchange. In addition, aquariums with sumps often use weirs over which the water flows, creating another efficient gas exchange area. The sump water surface will provide yet more gas exchange.

It follows that the system with the problem will often be found to have sluggish water movement. Therefore gas exchange is minimised. It may have been an attempt to economise with equipment, and if so this is not understandable, as the cost of say powerheads is low compared to other items and livestock. Definitely a false economy.

In a well designed system, be it ready built or aquarist built, there is no need to obtain oxygen test kits for regular testing, unless the aquarist has an interest in what the oxygen content of the particular seawater is. As said, it would be unusual for an oxygen problem to arise, although when water temperature rises above the design point a watch must be kept for any sign of distress, particularly in a fully stocked fish only aquarium.

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Tags: Aquarium Water, Equipment, home-aquarium, marine-aquarium, saltwater-aquarium, Water Quality

Reverse Osmosis

The reef aquarist in particular is always trying to maintain high quality seawater. So is the fish only aquarist, though the quality demand is not quite so vital.

The aquarist test the seawater parameters as a matter of course. Most aquarists find that all is well, or can adjust to remedy an incorrect reading. There are aquarists though who use high quality salt and are particular about the aquarium maintenance. Despite this, they find that problems arise, often in the from of phosphate or nitrate. They then obtain filters to deal with these, creating more expense and more maintenance. There is nothing wrong with getting rid of undesired substances with specific filtration methods.

The question is, where are those undesired substances coming from. As said, if the aquarist is doing everything correctly, including feeding, it is unlikely that it is being generated within the aquarium. So where does it come from.
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Tags: Aquarium Water, marine-aquarium, reverse-osmosis, saltwater-aquarium, Water Quality

Should You Use Natural Seawater In Your Aquarium

It seems very reasonable doesn’t it. We keep seawater aquariums and so why not put natural seawater in them. It saves money too, no more buying those expensive buckets of dry salt mix.

The first consideration is availability. Seawater is heavy, around 10lbs per gallon. If the aquarium is fairly large the amount required will be many gallons, much more if it is an initial fill. Lots of large containers, all suitably safe for seawater, plus a vehicle that can safely transport the bulk and weight. Most aquarists live away from the sea, and the dry salt mix is the obvious way to go.
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Tags: Aquarium Water, home-aquarium, natural-saltwater-fish-tank, saltwater-aquarium, Water Quality

Salinity In The Marine Aquarium

We all know that the fish and corals we keep are salt water creatures. That’s why we buy those expensive packets or buckets of dry salt mix.

Fish only or reef aquaria are normally kept at a specific gravity (SG) of 1022 to 1026. It has been said that it is advantageous to keep a fish only system at 1022, as it is claimed that certain pathogens do not do well at a lower SG. Fish can be treated for some infections by lowering the SG even more. Reef aquaria are normally kept at 1024 to 1026, this seems to be the usual. [Read more]

Tags: aquarium, Aquarium Water, aquarium-saltwater, mix-salt-water, mix-saltwater, water-change

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