Seawater, The Real Stuff

It doesn’t matter what the aquarium is for (as long as it isn’t housing freshwater fish!).  Be it a reef system, large or small or a fish only type there has to be seawater. Not any old rubbish either, it has to be high quality or the aquarist will soon learn of it in a not too nice way.

The majority of aquarists use pre-prepared mixes, that is a box with a dry mix to which high quality fresh water is added, the balance of one to the other is very important as it is intended to achieve a certain acceptable density. It is then heated and given time to mix and aerate before being added as a partial seawater change, or in a higher quantity as the initial aquarium filler. How can it be said that the majority of aquarists use a synthetic mix? There aren’t any statistics. It seems to be a matter of logic – how many marine aquarists live close enough to a clean unpolluted sea? A definite minority is the best guess.

There isn’t anything wrong with using the synthetic stuff, there are many beautiful aquariums using synthetic seawater. So what about the real stuff then?

Mother Nature is the boss of our aquariums whether we like it or not. Allow nitrate to climb and algae could appear. Allow the temperature to rise or fall moving out of the acceptable band and the livestock could die. Feed incorrectly and…..well, we get the idea.  So either the environment in the aquarium is acceptable to Mother Nature or there will be consequences.

Seawater is the major factor in an acceptable environment, quite obviously. So if all the life forms that live in the aquarium are healthy and happy, the seawater is also good. We keep the seawater good by partial seawater changes and regular test checks. It follows that if Mother Nature is quite fussy about seawater, what of her own? We’ve all seen pictures of healthy wild reefs and how beautiful  they are. The seawater must be really up to the job.

There have been quite a few comments on the internet about natural seawater. They state that the reef aquarium was healthy and lovely, but after the introduction of natural seawater there was something else. This ‘something else’ seemed hard to define, some extra growth and a more healthy and stronger colour to corals (and fish?). The whole thing, as one person put it, seemed more radiant. Why should this be? It seems no-one has any idea. The constituents of seawater are well known and that’s how synthetic mixes are achieved. Is there some constituent that has been missed? This is very doubtful. Maybe nature’s own is just superbly mature and a synthetic mix too raw.

So the logical thing having accepted that natural seawater is ‘better’ is to try using it. This is an immediate no-go for most aquarists as they are too far from the sea. Others would need a boat to get to unpolluted seawater. However, if there is a good accessible source of clean seawater obtainable why not try it?

It isn’t just a case of getting clean natural seawater, heating it up and adding it to the aquarium. Now would it be that easy, come on! Some equipment, pretty basic, is needed. First, the aquarist knows the amount of seawater used for a partial change, so a sealable container is needed for transport, one suitable for seawater. This could be already owned. Next, a suitable container to hold the seawater in for about week.

The seawater is collected from an unpolluted area (take more than required as some will be discarded), taken home and transferred to the holding container. It is left there, preferably in subdued light or the dark for, say, a week. This allows any suspended rubbish, big and small, to sink to the bottom. When a routine change is close, the seawater is siphoned from the holding container to the preparation container. It is important not to siphon too close to the bottom as any debris is obviously not required. The remaining seawater not siphoned is thrown away and a check made to ensure the container is clean.

Then normal procedures apply. The seawater is heated and aerated and when ready it can be put into the aquarium. The normal checks apply such as pH and specific gravity. It is likely that the checks will show a difference but if these are within acceptable parameters then no problem. Partial changes will alter things gradually.

So really the only extra piece of equipment required is a container to transport the seawater in. Hopefully this can also be used to let the natural seawater stand. Everything else is as usual.

All that is now needed is time. Has the reef shown any changes? Are things looking better? Any improvements will only happen over time and after many partial seawater changes have been done. It will be wonderful if change does occur and it hasn’t taken much more effort. Also, if successful, the cost of dry-mix salt will be saved.