Preparing for a power outage in winter

By Frank Greco, AnimalForum.com staff
Copyright 1997 by Frank M. Greco. Used with permission.

When winter is upon you, it's a good idea to make plans for maintaining your aquarium during a power outage. Even a short outage can lead to disaster and loss of animals if you are not prepared.

The first thing to do in an outage is to unplug your filters. If the power is off for long a long time, toxins such as hydrogen sulphide and ammonia build up in the filter. When the power comes back on, the filter will spew this toxic cocktail back into your tank, perhaps killing the fish. Once power is restored, clean out all filters before using them.

Preserving biological filtration is another matter. If you use rotating biowheels, remove them from the unit and submerge them in the tank proper. For fluidized bed filters, remove as much water as possible from the unit, leaving the sand covered by only 1/4" to 1/2". For trickle filters, you can pour water through them once an hour or so or wrap them in plastic film in order to maintain humidity. Of course, for any of these filters, hooking them up to a 12-volt bait pump (small bilge pumps) will ensure their continued operation.

During a power failure in cold weather, maintain temperature as best you can. Since glass is a poor insulator, heat loss can be rapid as the house temperature drops. Perhaps the easiest way to prevent heat loss is to wrap the tank in Styrofoam or some type of insulating blanket (the thermal type, such as are used to insulate water heaters).

Styrofoam can be purchased in sheets and cut to fit the size of the tank. Make sure it is a tight fit, and use duct tape to fasten the pieces together. Do not forget to insulate the bottom of the tank (if it is exposed) and the top. Punch a few small holes in the top for the airlines.

If you are using an insulating blanket, wrap it around the tank, using duct tape to keep it in place. While these methods will not prevent heat loss, it will slow it down. Never heat tank water on the stove and pour it back into the tank. Such wide temperature swings will virtually ensure that your fish will come down with a parasitic infestation. Better to allow the temperature to slowly drop, since the fish will adjust to it (to a point), than to play temperature see-saw.

Next, work on aeration and filtration. The simplest way to aerate is to remove buckets (or cups, if it's a small tank) of tank water and pouring them back into the tank from a height of 6 inches. Do this at least once an hour, more if the animals seem to need it. Another simple method involves hooking an airstone to a bicycle pump and pumping air into the tank as above.

The addition of 1 cc of 3% hydrogen peroxide per 10 gallons once an hour can also be used, but this is good only for short power outages since the addition of too much peroxide will destroy the biological filter. This should be used only as a last resort.

Perhaps the best way to aerate/filter your tank is to use battery-powered air pumps. There are two types available to the hobbyist, one of which works on "D" batteries while the other works on a 12-volt car or boat battery. Either will work, but the life of the "D" cell pump is short and you will have to replace batteries often. The 12-volt pump is better.

Hook your air pump to an airstone or boxfilter containing carbon and zeolite, or, better yet, a biologically active sponge filter and box filter combo. A 12-volt bait pump (bilge pump) may also be used to aerate/filter the tank, but they use more power than most 12-volt air pumps. The air lines should be run through the cover.

Unless you know the power will be off for a long time, do not feed the fish. Most fish can survive 3-5 days without feeding. If you must feed (for the health of the animal or your own piece of mind), feed sparingly. Remember, your tank's life support system has been compromised, and adding more organics will hasten water degradation.

If you follow my advice, your aquatic charges should make it through the power outage with little or no problems. Once the outage is over, do a 25% water change (remember to use your gravel cleaning siphon) and replace the carbon or whatever chemical filtrants you are using. Also watch for signs of disease (mostly Ich, which looks like white spots) and treat as necessary.