Nano aquariums are small, ranging from the very small of 10 gallons or a little less to around 30 gallons or so. They are popular, at least partly because they have the advantage of being able to fit almost anywhere, so the aquarist pushed for space doesn’t need to do without.
The big thing (if I can put it that way!) with a nano aquarium is they are relatively inexpensive to set up, stock and run. Having said that, all the considerations required for a large or very large aquarium apply, such as heating needs, stocking limits etc. Obviously the choice of livestock is restricted, for example a surgeon fish should not be in a nano.
The equipment considered for marine aquariums includes a protein skimmer. Though some manufacturers have improved, skimmers are often purchased with a capacity of around twice the aquarium net gallonage to make up for any ambitious claims by manufacturers. With some nano aquariums the difficulty would be finding a skimmer small enough.
That is often the problem – finding a skimmer that is physically small enough to fit the aquarium. With an aquarium of, say, 30 or even 20 gallons a hang-on skimmer could be found that will fit. However, the very small nano aquarium will often present difficulties, at least those that are being put together by the aquarist could. If a small nano aquarium is being marketed as a complete piece of equipment, and there are a few available, then perhaps the manufacturer has fitted a skimmer. The aquarist who is putting one together could check to see if that particular manufacturer also sells skimmers of the same specifications as a separate item. If so, perhaps there’s the answer.
Failing to obtain a suitable skimmer locally means trawling the internet to see which manufacturers produce what skimmers. Normally it is a hang-on variety that is used. If none suitable can be found what can be done?
The protein skimmer is an essential piece of equipment, and a great many aquarists support this view including me. This is all well and good, but what if a skimmer just cannot be found that will fit?
The first action that could be considered is the use of activated carbon. This media adsorbs dissolved organics and might be thought suitable instead of a skimmer. However, as I understand it the skimmer and carbon are effective on different organics. Nevertheless, in the absence of a skimmer activated carbon could be used. It should be regularly changed and preferably be in a pumped container such as a small canister filter – this will ensure adequate seawater flow through the media.
The second action is one that should be undertaken with any aquarium no matter what the size is, and that is to carry out routine seawater changes. The normal guideline for starting routine changes is 10% of the system net gallonage (this is often varied as the aquarist gains experience, both in personal knowledge and of the particular aquarium).
A great advantage of the nano aquarium is that it does not hold a lot of seawater, the very small ones as said perhaps 10 gallons or so. Obviously 10% of 10 gallons is 1 gallon. Doing a seawater change isn’t going to break the bank! So if there isn’t a skimmer and the aquarist wishes to minimize dissolved organic concentrations in the seawater, then the amount of each routine seawater change could be increased. This would have to be built up by the aquarist on experience, though there are some difficulties with this, as the test kits for organics commercially produced I am advised do not measure the organics that skimmers remove. Helpful! It should also be noted that seawater changes that are too large are not helpful because the mix is ‘raw’ and disliked by livestock. Generally 25% is the upper limit and this should be much more than enough.
The aquarist should ensure the minimum routine seawater change is completed weekly, and at the same time keep a watch for two things – first, the seawater should not have any slow bursting bubbles and/or oily and perhaps dusty looking film on its surface, and second there shouldn’t be any yellowing of the seawater, even slightly. This yellowing is termed ‘gilvin.’ If pale it is difficult to see and, though not required weekly, an occasional check should be made as follows. Take a white saucer or small plate and place it upright inside the aquarium at one end. Alternatively, tape a piece of white paper to the outside of the aquarium at one end. From the other end looking down the full length of the aquarium, check for any sign of yellow. It is unlikely that there will be if activated carbon is in use.
The protein skimmer is a wonderful device assisting the aquarist a great deal in the maintenance of high quality seawater. However, if the nano aquarium is just too small to make use of one, then the other advantage of the nano can be taken advantage of – very affordable seawater changes.