Keeping a seawater aquarium nowadays is a generally straightforward affair. Provided the design and setting up is satisfactory and the aquarist does the necessary periodic maintenance properly, the aquarium will give pleasure for a long period.
Commercial seawater mixes are good overall. The mix will provide adequate levels of elements in the seawater, but checks should still be made, particularly when the aquarium is matured and settling and onwards, to ensure that important parameters are as they should be.
The levels required depend of course on what is being kept. The fish only aquarist need hardly bother with any additives, just ensure that water quality tests are done (nitrates, pH etc) as these measurements are important, and action needs to be taken if anything is amiss. If [tag-tec]aquarium water changes[/tag-tec] are done it is likely that the seawater will remain fine, but maybe after a time from the initial mix end up, for example, with a fairly low calcium count. Alkalinity could also be low. None of this particularly matters if the fish are healthy and general tests are acceptable.
The aquarist who keeps a reef needs to pay more attention. No matter if there are fish present, the corals and other life create a need for closer attention. A soft or hard or mixed coral reef needs calcium, for example.
Soft corals do not demand high levels of calcium but it is worthwhile to maintain a fair level as there is a demand. I have always kept a notebook with each aquarium I have owned. I have a ‘thing’ for [tag-tec]soft corals[/tag-tec] so they are the type I have always stocked. Looking back at my records, calcium has generally been between 350 and 400 ppm. I did an experiment years ago with soft corals and calcium. Though I kept dates etc it cannot be deemed scientific, but should be considered as anecdotal.
I increased calcium by addition to 450 ppm for a period of 3 months, a period lengthy enough to have an effect. Routine water changes were regular at 10% weekly. The calcium level did vary a little but not much. I could detect no change in the health or growth rate of any coral. The calcium level was allowed to fall again and the notebook indicates no mishaps or worries arose. I know of a soft coral reef where the calcium level is a little over 300 ppm, The soft corals show no problems. If the aquarist wishes to raise calcium levels, it should be done slowly. There are commercial preparations that can be purchased and the aquarist should adhere to the manufacturer’s instructions in line with the net gallons in the aquarium. If the aquarist is serious about maintaining calcium levels and has a large aquarium, the use of a commercial [tag-tec]aquarium additive[/tag-tec] may be too costly and impractical. In this case consideration could be given to the use of a calcium reactor. If calcium levels are raised then attention needs to be given to alkalinity.
Please follow this link, an explanation is given about the relationship:
Also see ‘Alkalinity – What Is It and How Is It Controlled?‘ under Water Testing on this site (ie. Aquaristsonline).
With soft corals, some experts suggest the addition of iodine. Iodine in natural seawater is at very low levels, 0.06 ppm. As said, very low. Overdosing must be avoided when using commercial preparations. Again, strictly adhere to the manufacturer’s instructions. One problem with iodine supplementation is that, at least to my knowledge, there isn’t a reliable test kit available. If this is still accurate, the aquarist who is supplementing iodine according to instructions, and also doing, quite correctly, routine water changes, will not know if the iodine levels are rising, stable, or dropping. I would suggest not supplementing, and see if the corals remain healthy and growing. If they are, don’t supplement iodine.
There are commercial preparations available that claim to supplement important multiple trace elements. There is no dispute with that claim. However, if you feel you must supplement with one of these preparations, for example because activated carbon is being used, be aware of what is going into the seawater and also the reason why. If the manufacturer is worth his salt (no pun intended) the instructions will generally advise what and why.
Remember, with any supplementation be aware as far as possible of the levels in the seawater. This is not always possible with ‘trace element’ concoctions. Do not overdose, a little extra does not do a bit more good. Some aquarists advise that ‘if you can’t measure it, don’t use it.’
It is best to watch the soft coral reef, observing how the corals expand and grow. If all is well, routine water changes may be the only action required.
Finally, on any reef, soft coral ones included, there is normally more life than just the corals – snails, tiny shrimps, decorative algae and the like. Having increased and controlled levels of for example alkalinity can enhance the production of this additional life, all adding to the wonder and complexity of the aquarium reef.