Buffering Seawater

Marine livestock are used to very stable conditions. Much of this livestock comes from the wild reefs and there are literally cubic miles of seas and oceans to act as a sump. True, reefs can have problems created by mankind, such as industrial and agricultural run-off etc. This pollution has occurred over the short term, reef life has become used to very stable conditions over a very long period.

There are increasing numbers of locally produced corals and fish. These demonstrate a little more flexibility when faced with varying conditions because they have grown in an aquarium. Nevertheless, stability is a need for success with all livestock from whatever source.

The seawater is the area where this stability is of major concern, particularly in reef aquariums. In a fish only system the basic parameters need to be monitored, and in a reef a good few more. One of these is the buffering capacity of the seawater.

There isn’t any mumbo-jumbo on its way, the subject is straightforward and of importance to the reef aquarist.

A very quick look at pH first. pH is the measurement of acidity/alkalinity, and uses a scale of 0 to 14 (0 is acid and 14 is alkaline). Neutral is 7. Aquarium seawater can be between 8.0 and 8.4, with 8.2 or 8.3 often quoted as ‘perfect.’ So it can be seen that the seawater is on the alkaline side.

Life in the aquarium through its normal functions, feeding and the breaking down of dead algae etc puts pressure on the pH. This pressure continuously attempts to move the pH towards the acidic side of the scale. If the pressure has an effect on the seawater the pH will begin to drop. The pH will remain stable, at least for a time, because of the buffering capacity of the seawater. This ‘buffering capacity’ is also known as alkalinity and carbonate hardness. What happens is that the acids produced are negated by the ‘bases’, these are mainly bicarbonates and carbonates. Thus the pH remains stable.

The buffering capacity is finite. One way of boosting it is to complete regular seawater changes, though this in itself will not guarantee a continuing stable level. Sometimes it is necessary to engage supplements which are available from commercial sources. Supplementation should not be undertaken until it is certain the aquarium needs it. A slight fall in the level throughout a week or a fortnight which is repetitive is not a problem; this can be seen by the use of test kits. If the aquarist is having problems maintaining a steady pH or a proper level of calcium for example, scrutiny of the buffering capacity is in order. (Calcium should be in the area of 400 to 450 parts per million.)

In the aquarium it is considered beneficial to maintain the alkalinity a little above natural seawater levels because of the limited gallonage available. The level can be measured in meq/l or dKH. Any one is fine and the test kit will advise which scale is being used. They come to the same thing.

The levels recommended are 2.5 to 4 meq/l, which equates to 7 to 11 dKH. As said there isn’t a need to worry about the measurements, just go with what the test kit offers. Try and use a good test kit - questions on forums or to other local aquarists should produce recommendations.

The needs of a particular reef aquarium will soon be known and maintaining alkalinity becomes quite simple. Desirable algae, corals, snails etc will all benefit.

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Tags: Aquarium Maintenance, Aquarium Water, aquarium-additives, Care, saltwater-aquarium, Water Quality

How Do You Know When You May Need A Calcium Reactor?

A calcium reactor is a device which is used to provide much needed calcium as well as other elements dependant upon the media used. They work by slowly passing water through the media and recirculating it via a small pump. CO2 is slowly applied to the device to reduce the pH level in the device so that the media slowly dissolves. When the media dissolved calcium is released which is slowly passed into the aquarium system.

But how do you know if and when you will actually need one?

Well realistically it depends upon what you are keeping? If you are keeping a lot of hard corals then quite probably before long you will need to add one. If you dont keep hard corals then you may be able to control your calcium levels by water changes, additives, kalkwasser etc.

The best thing to do is actually test your water. If you find that you cannot maintain your calcium levels by performing water changes then perhaps you should try additives. If you find that you are having to spend a lot of money on additives then the next logical step would be either try kalkwasser or go straight for a calcium reactor.

If you decide to purchase a calcium reactor then there are loads available on the market plus there are quite a few desigs available now for those DIY enthusiasts.

There are some people who purchase a calcium reactor at the very start just because they believe that they need one.

I don’t agree with this as the only way to tell if you actually need on is either by your test kits or by the amount of money you are spending on other methods. If you are spending hundreds over the year then to be honest it is time to invest in a calcium reactor.

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Tags: Aquarium Maintenance, aquarium-additives, Calcium Reactor, Care, kalkwasser, Water Quality

Iodine Addition To The Marine Aquarium

The marine reef aquarist carries out routine changes to maintain the necessary high quality of the seawater. The life within the aquarium makes demands on the seawater and the aquarist needs to ensure that there is sufficient quantity to meet those demands.

Some of the additions to the seawater are well known and accepted. One of these is calcium. Others are not so widely accepted as necessary, and one of these is iodine.

All non-scientific people, which includes me, tend to think of iodine as, well, iodine. As in so many things, it is not as simple as that.

In natural seawater the level of iodine is very low indeed, at 0.06 parts per million (ppm). As already stated, iodine is not just iodine. It appears in different types which come under the iodine heading: these can be iodide, iodate, hypoiodite, and molecular iodine. Looking at that lot, personally I prefer to stick to the iodine label!

The main iodine types in natural seawater (they are all present) are iodate and then iodide. Many algae types use iodate, and the zooxanthellae in the flesh of corals are algae, so it follows perhaps that iodate is of benefit to corals in that way.

It is also said that iodine (using the overall label) is a requirement of corals as it assists them resist UV radiation. It is also said that it helps in their protection against some parasites.

University research, and the studies of some commercial enterprises, are said to support the above benefits of iodine in seawater. It seems reasonable that as iodine is present in seawater, then some form of life may well have made use of it. I am certainly not qualified to agree or disagree with any research findings.

There is a lot of discussion and disagreement over the use of iodine. Some aquarists have shown pictures on the internet of their display aquariums, and they are indeed beautiful. However, in the technical descriptions a great many of them do not include iodine as an additive that they use.

I used to dose my soft coral reef with iodine, but stopped for a period of three months to see if there was any change (this is not scientific, any apparent result is anecdotal). As far as I was aware, there wasn’t any change in the growth or health in the aquarium in general, never mind the corals. (I have to note that regular seawater changes at 10% are done and always have been, so there will have been some fresh iodine being introduced regularly, though I wouldn‘t have thought the natural seawater level could have been maintained.) I didn’t resume using an iodine additive. Now, two years later, I am going to do the reverse for three months, and see if I notice any change in anything. I expect I will not, but I’ll wait and see.

One thing that is clear. Iodine as stated is present in the seas and oceans in a very small amount. It is necessary to maintain the correct level in the aquarium, and overdosing could be disastrous. Therefore, bearing in mind that routine seawater changes are adding some iodine, it is necessary to test for the level. As the level is so low, a sensitive and reasonably accurate test kit is required. An ordinary hobbyist one will do nicely, but check it is suitable by obtaining opinion.

Whether the aquarist uses iodine as an additive or not seems to be optional at the moment. Perhaps in the course of time, scientific study will answer the questions about its use.

(Reference: Salifert, Nieuwgraaf, Holland)

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Tags: Aquarium Maintenance, aquarium-additives, Care, marine-aquarium, saltwater-aquarium