Power Outages and Saltwater Aquariums

How to deal with a power outage when you have a marine aquarium

Black and White Striped Fish in Fish Tank
 Glasshouse Images / Getty Images

It is a cold reality that aquariums (particularly marine aquariums) can't operate without electricity. From air pumps, to powerheads, to protein skimmers, to automatic feeders to the lights we use to illuminate the tank, all of the things we use to make the tank run properly and keep all of the tank critters healthy and happy require electricity of one kind or another. For the most part, a vast majority of aquarium equipment runs on AC electricity, the same as almost all of the lights and appliances in your home do. When the lights go out, your aquarium stops functioning.

What Your Aquarium Needs to Survive

There are certain functions in a saltwater aquarium which are essential for its survival: gas exchange and water movement. Even the most sensitive corals in a reef tank can survive for days without intense light, but the viability of fish, invertebrates, corals and beneficial bacteria deteriorates rapidly without a reasonable supply of oxygen. This being the case, in the event of a power failure, the primary objective (both short and long-term) for the aquarist is to supply oxygen to the tank and move water (even periodically) about in the tank. This is bare bones survival and some of your tank's filtration systems (wet/dry trickle, canister filter) will not be functioning. The nitrifying bacteria which resides in the tank (on the live rock, tanks walls, etc.) will live and continue to process ammonia, nitrites, and nitrates if O2 is supplied at least periodically.

For most tanks, when operating properly, a vast majority of gas exchange (CO2 out and O2 in) takes place at the water surface of the tank. Protein skimmers and wet/dry trickle filters also contribute to gas exchange during normal operation, but will not be functioning during a power loss. You can supply O2 to the tank and provide some water circulation manually. Here is one method which is easy to do and actually works:

  • Take any type of clean container and use it to scoop up some aquarium water.
  • Hold the filled container some distance above the aquarium, and pour the water back into the tank. Repeat this process numerous times.

More Oxygenation Tips

  • A larger volume of oxygen is generated the higher the water is dispensed from above the aquarium, and the number of repeated times this is done.
  • There is no set rule on how often this should be done because every aquarium is different. You'll need to judge for yourself at what intervals each hour is going to be best for your system. When in doubt, go ahead, and if the fish start coming to the surface gasping for air, it's definitely time to aerate some more.
  • To avoid messing up the substrate and stirring up a bunch of crud, particularly if you have a small or shallow aquarium, place a small plate or bowl in the tank and pour the water onto this area. Ceramic or glass items work well for this because the item has to be heavy enough to stay submerged and in place.

Real-Life Examples

Emergency Power for Aquariums From Adam Goldstein tells how his aquariums have survived multiple power outages, some for up to 3 days. Adam utilized 2 Odyssey automotive batteries (Compare Prices) with a 925 cold cranking amps rating and a 400 Watt DC to AC Power Inverter (Compare Prices). With this setup, Adam could run his normal AC pumps and filters but did not turn on his tank lights (they used too much electricity). While Adam recharged the batteries in his car he also suggested that the batteries could be recharged using a solar panel. Adam explained that normal automotive batteries should not be used indoors, as they emit sulfuric acid fumes (bad stuff), but the Oddysey batteries are sealed (don't emit fumes) and are therefore safe to use indoors.

While not a viable option for many people (like those who live on the 32nd floor of a high rise apartment building on Manhattan Island), having a gasoline-powered generator on hand may be the best long-term solution for dealing with a power outage. To be sure, they are not inexpensive, but for $400 to $500, you can purchase a 5,000 watt generator which will not only keep your aquarium(s) running normally, but also power a majority of the electrical appliances (refrigerator/freezer, TVs, computers, lights, stove, even the heat, and A/C) in your home. When you consider how much money you have invested in the critters in your marine aquarium, it's not a stretch to realize that a $500 investment in a generator is really cheap insurance. We lost about $375 in fish and invertebrates as a result of Hurricane Irene. We now have a generator. Plan for the worst and hope for the best.

If you do purchase a generator, you might want to seriously consider having an external 220-volt receptacle hard-wired into your house electric panel. This way, you won't have to leave a window open for all of the extension cords to run through. You will be able to run a lot of your electric devices with your normal outlets. When the power goes out, all you have to do is roll your generator out of storage, plug it into the receptacle and fire it up. Make sure that you trip your main circuit breaker, though. Otherwise, you will be supplying power to a lot of other people through the power lines. If you are not extremely comfortable with electric wiring, hire a licensed electrician to make your wiring modifications.

If you don't want to make the investment on the off chance that you will be hit with a long-term (more than a few hours) power outage, there are many retail outlets (Walmart is only one) that offer to refund your purchase of a generator if you return it in an unopened box.

No matter what your solution is to deal with a power outage, whether it is caused by a blizzard, hurricane or total power grid failure (yup... it has happened), the key to survival is to plan ahead.

Here are some successful methods that other aquarists have used to keep their aquariums running during a power outage.