Almost anyone who owns reef knows someone who has had their entire tank wiped out by a power outage. We've had several recent ones here on Captive Reefs. No matter where you live, you are eventually going to have a power outage, and how well your tank handles it will depend on how prepared you are. A prepared reef owner needs to have a plan and a few necessary pieces of equipment on hand for dealing with power outages.
Power outages are often caused by a storm, but can also be the result of work being performed on the electrical utility, an accident, or an over-loaded electrical distribution system. Most of these power outages are relatively short, however can last days. These types of outages cannot be prevented. Knowing what will happen to reef tank is critical to developing a strategy to deal with a power outage.
What's the Big Deal?
The main concerns with a power outage is oxygen depletion and equipment failure. How long a tank can go without power depends on many factors including stocking level, size, and room temperature. Some tanks with heavy stocking may begin to have problems in as little as an hour. However, most tanks (average stocking) can go for a few hours without a problem. Even in very hot or cold weather (which is, unfortunately, when most power outages occur), fish require oxygen to survive.
Another concern with a power outage is whether or not equipment will malfunction or restart. It is recommended that you simulate a short term power outage occassionally to make sure your plumbing and electrical systems are properly functioning. By turning off all of the power for several minutes, you can check your plumbing to make sure you do not have any water siphoning back that could drain your tank or chemical feed systems that create a siphon when flow is not present or reversed. Proper air gaps are the best way to avoid a siphon as check valves can be unreliable. When you start your tank back up, you can make sure that the pumps and other equipment will function properly. An already stressed circuit breaker could trip if all equipment is turned on at the same time (as will happen after a power outage). If your equipment does not perform adequately, fix the problem now before a flood or catastrophe happens while your away.
During longer power outages, other factors such as flow and temperature come into play. Corals need flow to survive. Even in a fishless system, if the water sits without flow longer than a day or two,coral and other inverts will begin to see a negative outcome. For sps this timeframe is likely less.
Tank temperature becomes a concern with longer power outages. Unfortunately, most power outages occur is during the coldest and hotest weather. The time frame when temperature becomes an issues is completely dependant on the ambient temperature of the room.
In long duration power outages where the above factors aren't mitigated, it becomes more likely that multiple factors will contribute to death of livestock. In fact once livestock starts to die, it could cause a crash as biological filtration is not going to properly be able to keep up with demand. This can also be a concern if you are away (e.g., vacation) and the power fails then comes back on but was off long enough for fish to begin to die. In extreme cases, an entire reef can be lost.
Fortunately, although you may not be able to prevent a power loss, there are ways to prepare yourself for the inevitiablity of a power failure.
One of the least expensive options is to purchase a battery powered air pump, Models are available that will automatically turn on if the power fails. One such air pump is MillionAir AC/DC Auto Switch Battery Air Pump which uses two "D" size batteries. An air pump will help aggitate the water surface and provide some flow to aid in air exchange and maintain oxygen levels. You'll want to plan on one air stone for every two feet of tank length to maintain safe oxygen levels. Also be sure to have a few extra batteries on hand and check them periodically to make sure they work.
Invertors (or DC/AC Converter) are inexpensive and flexible devices often overlooked by reef hobbyist. Converters that will power 400 watts of devices can typically be had for $35 on eBay.com web site. These devices can be hooked up to an extra car battery or marine batteries. Or better yet, directly to a running car via a cigarette lighter port if you can park within an extension cord distance. DC/AC power converters can also be a cost effective way to run a heater. You can also use them to recharge your UPS. Be sure to have your car in a well ventilated area while it is running in park!
UPS/Battery Powered Pump
Uninterupted Power Supplies (UPS) units are designed to automatically kick in when the power goes out. UPSs are commonly used for computers to prevent data loss Computer UPS's generally don't have a high capacity battery as they are meant to provide enough power to safely power down your computer. UPSs are available that can be connected to external batteries. In fact you can connect the batteries in parallel to get longer run times. If you are present when the tank is running on UPS, you could manually turn the power on to extend the battery life of your backup. Turning the pump on for 5 minutes every half hour should be sufficient to provide life support to your reef.
However, UPSs are best suited for running a small pump or two for a period of time (how long depends on the battery). It is not going to last long if you hook up a heater or chiller to it. So it is probably not viable solution for long duration power outages in extreme temperatures.
There are several commerically availble pumps such as the Ecotech Vortech that offer backup batteries for their pumps. These pumps run on 12 volts so it makes it easy for them to connect to a battery power source. Most controllable pumps can be configured to run directly off a battery. Tunze offers an adapter for their controllable pumps to operate from a backup battery supply. These pumps have a remarkable run time on battery power...for example a Vortech MP10 can run up to 3 days on the backup battery.
Generators come in two flavors...portable and permanent. Generators range in price from $100 for a small portable unit up to thousands of dollars for a whole house permanent generator. Either option will allow you to run heaters and pumps...skip the display lights as they are not necessary in a power outage.
The main difference is that a permanent generator will generally start automatically during a power failure so that the tank continues as if nothing changed. Where as a portable would require you to hook it up and manually start it. Permanent residential generators generally use natural gas or propane for fuel...although gasoline and disiel models do exist. Where as most portable generators are going to have a fairly small tank and run on gasoline.
In a Pinch
Here are some items you can do if you haven't obtained any of the items above:
- Manually oxygenate your water with a cup or pitcher. Simply take a few scoops and pour it back into the top of the tank. Allow it to fall a little to pick up. Doing this every half hour will help preplenish oxygen levels.
- During a power outage, keep your tank dark. By covering the tank or closing the curtains, it will help keep fish in a less active state and therefore keep them from using as much oxygen (swimming around uses more oxygen and produces more carbon dioxide than resting under a rock).
- If it's cold, wrap the tank in blankets to help conserve heat.
- Use a battery powered light (flashlight?) and a ball of macro algae. Algae consumes carbon dioxide and produces oxygen during photosyntheis. This combined with a backup air pump may also increase efficiency. Although this option isn't likely vary viable for anthing but a nano tank because of the amount algae required to be lite for a large tank.
- Reefkeepers who are also divers may want to rig a device that will aerate their aquariums with a airstone from a SCUBA cylinder.
- Try to borrow a portable generator from a reefing buddy or neighbor. It helps to offer to purchased some gas.
While a whole house generator is obviously the best solution, it is not a viable one for everybody. Combining the other methods discussed above can provide life support for short and long term power outages. The key is to have a plan in place and the necessary equipment to implement it.