An Attached Quarantine Tank

1160292_82946141Having a quarantine tank is generally accepted as ‘a good thing’. Strangely, the majority of marine aquarists don’t use one, instead throwing caution to the winds or at least relying on good luck. Perhaps they obtain their fish from sources where they are guaranteed to have been successfully quarantined.

Anyway, this isn’t about the merits of quarantine, this is about continuing usefulness.

Quarantine tanks don’t need to be large, just large enough to comfortably hold the largest fish that will occupy them. All the same, it is a little irritating to have an available space doing nothing – the tank sits there empty. The tank can of course be used as a hospital tank should the need arise, but this is hardly ever needed particularly if quarantine has been completed on carefully selected and compatible livestock.

An idea came up recently about a way of using a quarantine tank as part of an overall system so that it wouldn’t sit and ‘do nothing’.

The tank would be selected to ensure it could accommodate anything likely to go in it. It would then be connected into the main system permanently. Err, sorry, what was that again?

Instead of the quarantine tank sitting empty most of the time it would be connected to the main display system as a permanent feature. This gives the advantage that the system would hold more gallons of seawater. It would not be intended to be stocked with anything, just have seawater flowing through it. (Hmm, how long would that last I wonder, aquarists tend to fill empty spaces.)

The tank would be fed seawater that was circulating through the display aquarium and any sump. See the first problem? Of course you can, any problem in the tank would become an available problem throughout the system. Disease for example, the very thing that the quarantine tank is designed to prevent entering the main display.

The idea went on that this problem could be prevented by using a UV (ultraviolet) sterilizer. UV sterilizers (some call them filters) kill or severely damage unwanted organisms as they pass close to the UV light (they do the same to good organisms as well). The seawater exiting the quarantine tank would flow through the sterilizer and therefore anything unwanted would be dealt with. On the face of it this isn’t a bad idea.

The first problem is that the flow rate through the UV unit has to be correct. This is because in order for the UV unit to be effective organisms have to be exposed to the radiation for a long enough period. Therefore the flow rate would probably have to be slowed down.

The second problem is that good as a UV sterilizer is there isn’t a guarantee that all organisms passing though will be killed or sufficiently damaged. Most probably would be or the UV sterilizer wouldn’t exist – but there isn’t as said a surety that all will be properly dealt with. So the system as a whole would be at risk.

The next is not really a problem, more a discipline. The aquarist would need to ensure that the UV bulb, which has a specific life, was renewed well in time or its effectiveness would reduce.

So the basic idea is flawed. However, how about a small modification? How about placing a shut off valve on the outlet from the tank? This would require a complication which is another outlet for the seawater to go through the UV unit. This would be easily achieved by fitting in a correctly rated powerhead to run seawater through the UV unit and back again. Oh, there’d need to be a shut off valve on the inlet to the tank too or it would overflow. Things are getting a bit too complicated. With the shut-off valves at each end of the tank it is now independent of the system.

Many aquarists use a UV unit fulltime or part time or as necessary. Fine, there’s no problem there. Many aquarists don’t use them at all. It’s a choice. But the UV sterilizer is not an answer to the quarantine question.

The only way a permanently attached quarantine tank could work, as far as I can see, is to have stop valves on the seawater input and output. Therefore the tank could not be plumbed directly in line with the display aquarium and sump, it would have to have a direct feed to and from the seawater source which wouldn’t interfere with overall system circulation.

Under normal circumstances (that is, empty without livestock) the quarantine tank would be full of seawater flowing through it, which is an advantage to overall gallonage. If the time came to use it as a dedicated quarantine area, the first action would be to turn off the input and output valves to isolate the tank.

Another problem now arises and that is seawater circulation. Now that the tank is isolated there isn’t any circulation so there would need to be available a low powered powerhead to deal with this. The next problem is that the circulating seawater would cool down, so a small heater would be needed. Then, for the security of the quarantined fish, a suitable clay pot, for example, would be needed as a temporary home.

Light needs to be considered – is there enough light over the quarantine area? Would any need to be added for the comfort of the fish?

Once the quarantine period was over, before the inlet and output valves were opened, all the seawater in the quarantine area would need to be removed. Most could probably be siphoned out. It would be important to dry out the tank entirely particularly if any copper treatment had been used, and probably rinse the area out as well. Not particularly difficult, but another necessity and complication.

All of this leads to the thought that it would be better to stay with the unattached quarantine tank. They are usually small and can be put out of the way somewhere with the powerhead and heater inside.

Having an additional tank attached to the main system isn’t a bad idea, as said it increases gallonage. Also it could house further filtration or even special livestock of interest to the aquarist. There wouldn’t need to be inlet and outlet stop valves either!

There is one thing that must be said and this is that thinking ‘outside the box’ is one of the ways that the hobby progresses, so the aquarist who mused over this idea is to be congratulated – the idea is not practical when examined, but it is an idea.


An Attached Quarantine Tank
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