If you have been in this hobby long enough, you or someone you know has probably experienced some sort of major aquarium disaster.

Whether it is a loss of livestock, failed equipment or damage to your home (hardwood floors and water don’t mix), many of these unfortunate events can be prevented by setting up redundant or backup systems and having spare equipment available.

Although we hope for the best, today we are going to share some of the lessons we have learned—sometimes the hard way—about how to prepare for the worst.

We help customers plan and upgrade their aquarium systems to be more fail-safe all the time. Plus, since we have been through the wringer a time or two ourselves, we felt a responsibility to pass along this knowledge to hopefully help you prevent your tank from crashing some day.


A stable temperature is KEY to a successful reef tank. Fluctuations up or down may cause devastation to your aquarium. Some species are more tolerant to change, but delicate fish and corals need a very stable temperature.

A reef aquarium can be wiped out quickly if the temperature rises too high. Outbreaks of disease may occur and spread quickly when dramatic temperature changes take place. It is, therefore, essential to keep the temperature steady in your tank at all times.

To be mindful of your aquarium temperature, you can focus on three areas: your thermometer (to measure the temperature), your heater and ways to help cool the tank down.

  • Using a controller to monitor and control your tank’s temperature is just one safeguard, but even a controller can fail. Using multiple thermometers in conjunction with a controller can help monitor your aquarium water temperature more effectively. Using a digital thermometer with an audible alarm is even better!
  • Instead of using a single heater (for medium to larger aquariums), using multiple smaller heaters can help prevent overheating or no heating if one fails. For example, if your tank requires 300 watts of heating, using three 100 watt or two 150 watt heaters instead of a single 300 watt heater is generally a better choice. Another option that is more along the lines of redundancy is to have two sets of heaters for the tank with different set points for turning on and off. The “second” set can swing in to action if the first set fails keeping the tanks temperature from falling too low. It is also a good idea to keep a couple of spare heaters on hand, just in case.
  • Having backup fans for evaporative cooling in case your chiller goes down (or if you don’t own a chiller) can help in a bind to keep your tank’s temperature in a safe zone. Another trick is to have your aquarium controller shut off your lights if/when your tank temperature gets too high.


Aquarium lights are one of the most important pieces of equipment for a reef tank. Many reef inhabitants depend on the light you provide for survival. Although corals can survive without light for a couple of days without trouble, any longer and they may begin to feel the effects. Don’t leave your corals in the dark: stock up on backup bulbs and ballasts so you can turn the lights back on quickly in case of equipment failure.

  • Bulbs: Keeping extra aquarium light bulbs on hand in case one goes out is a must. Having backups allows you to exchange burnt out bulbs without having to wait for replacements to arrive. If you have old bulbs that still work, hang on to them until the next cycle of bulb swaps. You may be able to use one in a pinch. Metal halide and fluorescent bulbs contain mercury, so please recycle your used bulbs to ensure they do not end up in landfills.
  • Ballasts: If you use a single source of light for your aquarium (like a single metal halide bulb, for example) having a backup ballast in case yours fails can definitely help to save the day.


Using aquarium monitoring devices to keep a close eye on key water parameters like pH, nitrate and salinity is a wonderful way to help keep your aquarium water chemistry stable. They give you a glimpse into the overall health of your system and can help identify a rising problem before it becomes disastrous.

A dramatic overnight swing in pH, for example, can indicate a dropping alkalinity level in the aquarium; a change in average temperature can indicate a heater or chiller failure.

To ensure these devices are recording accurately, just use good old-fashioned aquarium water test kits once per month to verify the results. While using a monitor may seem redundant enough, it is always a good idea to ensure the equipment is working properly and is calibrated correctly in order to protect your precious reef. Not to mention a variety of parameters cannot be monitored electronically. Water testing usually becomes routine for any successful reefer.


You might consider your return pump the heart of your aquarium system. If circulation shuts down, oxygen levels can drop fairly quickly. Should the oxygen level get too low, livestock may begin to suffocate. Witnessing your fish gasp for air at the water surface is heartbreaking.

There are many reasons a return pump can fail, from a broken impeller to simple burn out. Regardless of the cause, the important thing to be aware of is an aquarium can crash quite rapidly without any water circulation. It may be outside the budget of some hobbyists, yet depending on how much you have invested in your reef, purchasing a spare return pump can literally be a lifesaver and save you a fortune in the long run.

If your return pump is rather pricey and a backup of the same make/model isn’t feasible at the moment, you might consider less expensive alternatives for your backup pump. Providing a temporary fix while you get your main return pump serviced or replaced offers great peace of mind. Pumps like the MagDrive or Rio are perfect to keep on the shelf for these types of emergency situations.

On the same note, having extra circulation pumps/powerheads to keep the water moving within the tank in the event of an emergency is highly recommended. Our staff uses Hydor Koralia, Cobalt Aquatics MJ or Marineland Maxi-Jet pumps for backup and utility purposes. They are reliable, affordable and can keep your fish and corals content while you repair your main system.


Raise your hand if your ATO system has caused a flood in your home or office. Don’t feel bad: you are not alone!

Sadly, auto top-off systems can and do fail. Whether you are filling your aquarium directly from a RO/DI filter, topping off from a reservoir or simply filling a portable container to mix saltwater, no system is completely foolproof.

Using an ATO system with a redundant float valve or sensor (or picking up a second to add to your existing system) can help prevent flooding. If you are dosing kalkwasser from your top-off water, I highly—and can’t stress this enough—recommend having a redundant float valve running. I have seen some absolutely beautiful reef tanks destroyed by an overdose of kalkwasser because of a failed sensor or valve. Don’t let it happen to you!


I lived in Southern California for nearly a decade and currently reside in the Northeastern United States. Needless to say, power outages are something I have grown accustomed to. From earthquakes and hurricanes to tropical, snow, wind and/or lightning storms, I have faced off with Mother Nature in just about every way possible except for a typhoon (knock on wood).

Power outages caused by these sorts of events generally last only an hour or two. However in 2012, Hurricane Sandy left my home without power for nearly 10 days. Fortunately, I was prepared. My backup generator kicked on and literally saved my fish tank. I did not suffer a single loss during that stressful period.

Even if you don’t have the space or means for a backup generator, there are other more affordable backup devices available that you can use to keep key pieces of equipment running in the event of a power outage.

EcoTech Marine’s Battery Backup can keep your VorTech pump going for up to 60 hours after the power goes out (30 hours for two pumps). You can even add a second Battery Backup to double the run time.

An uninterruptible power supply (UPS) is another way to protect your aquarium in the event the power goes out. Although typically marketed toward computer users and businesses, large UPS devices can keep a small water pump or air pump running for hours.

Another inexpensive and popular backup device is a battery-operated air pump. Like the aforementioned devices, a battery air pump can help keep the oxygen level in your tank in the safe zone while your main system pumps are inoperable, just be sure to have plenty of batteries!


Storing fresh top-off water and having extra saltwater prepared for emergency water changes are among the best decisions you can make as a reef aquarium owner. You don’t necessarily need to experience an equipment failure or suffer through a power outage for your reserve water supply to save the day. You may simply be returning home from a long day at the office or a weekend away with the family to discover a problem in your tank; such as the untimely death of an anemone or accidental over dose. Giving yourself the tools to rescue your tank at a moment’s notice can truly be the difference between life and death.


Aquarium controllers have come along way in terms of how they can help prevent a disaster in your aquarium. The benefits of monitoring your water parameters and controlling your equipment from a single device saves you time and energy. Integrating leak detectors and float switches to prevent floods or burning out pumps can easily prevent an expensive mistake.

The real lifesaving features of a controller comes into play when you have remote access and alerts set up. Advanced controller systems offer the ability to access your controller via the web and set up alerts to notify you by email or text when changes occur in your aquarium. You can even turn your equipment on and off from a remote location and view all of your water parameters to give you peace of mind that your tank is running smoothly no matter where you are.

With all of the time, money and effort we dedicate to becoming excellent stewards of aquatic life, investing in redundancies, backup equipment and power supplies to prevent and resolve aquarium emergencies should really be a no-brainer.

RELATED READING: 7 ways to be prepared for an aquarium emergency