Power Outage Preparedness

Some aspects of this hobby are often overlooked until problems actually arise. Marine aquariums require a lot of time and dedication, so it is easy to understand how small things may be missed. But, sometimes small things can snowball into a disaster. If the aquarist had been prepared sooner and had the proper equipment on hand, a lot of these problems may not actually be an issue. One of the most common mistakes a lot of hobbyists make is putting off buying equipment needed to keep tank life support running in the event of a power outage, until it is too late. All too often newer and seasoned fish keepers alike find themselves in the middle of a storm, with no electricity, and no way to keep their tank warm or oxygenated for hours (maybe even days) until they have power again. This article is geared towards helping you put together an emergency power outage kit that can keep your tank alive during the inevitable, which can save you from a total system crash.


To start off, don’t worry about lights. Even SPS corals can go a few days without any light. Unless you are in a disaster stricken area and power is projected to be out for more than three or four days, do not worry about lighting!


This is probably the most important thing to think about. I personally keep battery operated air stones on hand at all times, with extra batteries. As soon as power goes out, drop them into the tank. Battery powered pumps can be found at big box pet stores and recreational fishing equipment shops. If you find yourself reading this after your electricity has already gone out and you have no way of getting these amazing little devices, don’t worry! Oxygenation can be done manually. Grab a clean bowl or cup and fill it with tank water. Holding it up high in the air, dump the water back into the tank and repeat for a minute or two. In my opinion it is best to do this a few times every hour (more often for larger tanks and fish). Watch your tank closely, if fish start to swim near the top of the water column or “gulp air” you will need to do it more often as this is a sign of suffocation.


Most marine aquariums are kept between seventy five and eighty degrees Fahrenheit as this mimics reef conditions. During a power outage, heat can be lost quickly as house temperatures also dip. For small nano tanks, taping a few hand warmers to the outside of the glass can keep temperatures up and help protect against rapid temperature swings that larger tanks don’t typically suffer from. If you have absolutely no power source at all, wrap larger tanks in thermal blankets to conserve heat as long as possible. In addition, glass lids and canopies should be placed on top of tanks, if available, to prevent heat from escaping.  While dropping a few degrees over a few hours is not usually dangerous to fish or invertebrates, winter months or cold climates may cause a ten degree or more drop within a few short hours and can definitely cause problems.

Water Movement

While oxygenation is important, it is equally important that this oxygen is transported throughout the aquarium so all inhabitants can use it. Otherwise, oxygenated water will sit near the top of your tank and oxygen deprived water will settle in the lower half. Corals, bacteria, and invertebrates may not have a way to get to oxygen rich water and may suffocate in stagnant water if power is out for more than a few hours. All aquarists should have a powerhead in their tank (either battery operated or connected to a power source) and make sure sure it is operational in the event of a power outage.

Potential Power Sources

Even though your electricity is out, it doesn’t mean your tank has to go without power. Many devices are able to provide electricity to your tank for anywhere from a few hours to a few days. While manual fixes talked about above may save you in an absolute emergency, you should always prepare in advance by having one of the following items on standby. Most experienced hobbyists have at least one or two of these as they can easily save you money and heartache by preventing total system crashes.

Power Inverters

These nifty devices are able to use your car battery to power your tank. They take the current from your car battery and convert it to AC power, and have an outlet(s) you can directly plug your return pump into. Running your return pump should be priority if you live in a warmer area as it provides oxygenation and water movement. If it is winter, or cold where you live, run your return pump for an hour or two and then your heater for a few hours to maintain warm temperatures in the tank. If you have more than one car or car battery, be sure to charge one while the other is in use as it will eventually die and need to be charged again before using it a second time.

Battery Backups

Many aquarium equipment companies produce battery back ups. These simply mount to your stand and you plug your wavemaker(s) into it. Although typically only usable by DC pumps made by one specific brand, these are relatively inexpensive solutions that many hobbyists employ. Remember, if you only have a powerhead plugged into this, heat and an oxygen source must still be added.

Uninterruptible Power Supply

UPS systems are made for computers. But, these are great little devices to use on marine aquariums as well! They are surge protectors, and have saved tanks when heaters explode or shorted out. And, the battery built into them can power small heaters, air stones, and wave makers for a short period of time. If you live in an area where short, overnight power outages are common like I do, these can help you sleep through the night during storm season without worrying about your tank. They automatically recharge if the battery dies as soon as electricity is returned. These are not meant to power large pumps or lights for any length of time, so be sure to check the load of whatever you plug into it and the estimated battery run time.

Gasoline Generators

Usually the most expensive, but most appropriate option, gasoline generators are a must for anyone living in areas where extended power outages are common in my opinion. These can easily run entire tank systems, along with refrigerators and household appliances until power is restored. Cheaper generators can be purchased for around two hundred dollars, while systems able to power entire houses can run a few thousand. If you only need one exclusively for your tank, a small one is typically more than enough to power everything except lights that consume a lot of power (such as halides).

Other Things to Think About

Many systems relying on manual oxygenation or that have a lack of water movement may experience small ammonia spikes as it is common for some beneficial bacteria to die off. Longer power outages usually create bigger problems, but a good ammonia test kit should be on standby no matter what as ammonia is extremely toxic to fish, corals, and invertebrates. Keep ammonia reducing or binding water conditioner or media handy in case this happens. I personally always have Seachem Prime next to my tank just in case. Prime is able to bind ammonia, nitrites, nitrates, and heavy metals and make them non toxic for about one to two days until it is re-dosed.

Remember not to feed your tank during extended power outages. While they may beg for food, it could cause large ammonia spikes and they will be just fine without food for a couple days.

Final Words

While spending another one to three hundred dollars on these alternate power systems may seem like a lot of money for a worst-case-scenario, it is a small investment compared to the hundreds, likely thousands of dollars you have spent on the tank inhabitants themselves. All of the time, effort, love, and frustrations that we have spent on our marine aquariums could easily be wiped out and killed by being unprepared for a power outage. Even if you have to save up extra money for a few months to purchase one of these items, I believe it is a small price to pay for the insurance they give us in protecting, and potentially saving, our aquariums.

15 thoughts on “Power Outage Preparedness”

    1. Tabitha Shafer

      One point missing here is a chiller. I live in Florida and heat can kill too. Once you lose power your house starts to get warm and so does the temperature in your tank. A chiller is a must here in power outage, or even if your A/C breaks down. We have a gasoline powered generator that can run our tank and chiller.

  1. Nathaniel Konkel

    Battery backups or UPS’s seem like a great solution for many people, but often these are warned against “use on aquariums” by manufacturers.
    Why would they do that?

  2. Nathaniel Konkel

    Battery backups or UPS’s seem like a great solution for many people, but often these are warned against “use on aquariums” by manufacturers.
    Why would they list that as a hazard?

  3. fishtankpsycho

    This is one thing I have never prepared for. I definitely need to though. Battery backup packs really aren’t a bad investment.

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