Disaster Readiness

by | Aug 15, 2002 | 0 comments

It could be 2 AM on a cold winter night, a spring-time tornado, or perhaps a late season hurricane: whatever the cause, the instant the power goes out your heart skips a beat and you think about your tank.

If you never considered such scenarios before, it might be time to panic. If you’ve planned for it, or at least considered your options, you’ll probably be in good shape. The big unknown with a power outage is how long it will be out? It could be a few minutes, an hour, or possibly several days. The uneasy wait for electrical power to return can be very stressful.

Oddly enough, a power outage got me into the salt water hobby. I formerly raised African cichlids. I had a beautiful display tank and a fry tank. But I was totally unprepared for a power outage and never considered, much less planned for, an ice storm which took out power for a full week. Years of work were lost. Beautiful mated pairs of exotic fish lay frozen on the substrate, and not a single fry survived. That night my wife tried to comfort my loss and suggested I try that saltwater tank I always dreamed about (she has grown to regret that suggestion.)

Could this loss have been prevented? Perhaps. The fact that I had no plan in place set me down the wrong path from the start. Will I have better luck next time? Perhaps. At least now I have a plan in place and a fighting chance of making it. The stakes are much higher now with a fully stocked 180 gallon reef tank.

The best way to prevent a tank disaster is to be ready for a natural disaster. Anything short of a natural disaster should be that much easier to handle. How you prepare for all this will depend on the time of year. No need worrying about an ice storm during mid-summer. The actual threats to your livestock also change with the seasons. For example, in many regions, maintaining temperature is much harder and more critical during the winter than it is in the summer.

Except for the uninterruptible power supply (UPS) or generator everything else listed in the Disaster Prevention Checklist should cost you under $100 US. That’s likely an insignificant price compared to the total cost of your tank. These basic items alone should be more than enough to get your tank through the summer thunderstorm power outages or typical winter outages that last less than 5 to 8 hours. Beyond that things get tricky and a little more expensive. More on that in a little bit.

Disaster Prevention Checklist:

  • Batteries for radio
  • Batteries for flashlights
  • Batteries for air pumps
  • Blankets
  • Styrofoam sheets
  • Air pumps
  • DC/AC Power Converter
  • UPS or Generator
  • Portable Room
  • Heater

Let’s start with a review of the Disaster Prevention Checklist. A battery powered radio of some type is crucial for staying current with weather events and local warnings. Have extra batteries ready for your radio. It seems most power outages happen late in the day or at night. Flashlights are much safer than candles. Have enough flashlights on hand for each member of the family and extra batteries for everyone. I would also suggest having two flashlights dedicated to the tank area. Battery-powered air pumps are very cheap and highly affective in generating water current in your tank. Have plenty of batteries for these. While you’re at it, I’d suggest having extra batteries for your kid’s Game Boy or MP3 player. If you plan carefully most of these devices will all use one or two types of batteries which can be purchased in bulk at most home improvement centers or discount stores.

Blankets and Styrofoam sheets will help conserve tank heat during the winter months. I suggest you get Styrofoam sheets used in home insulation. These sheets are easy to cut to size to match your exact needs. I suggest one sheet for all four sizes and one for the bottom. If your hood can be removed easily, one for the top may be a good idea as well. These Styrofoam sheets are easy to attach to the tank with masking tape and can be stored out of the way in the garage or attic until needed. Most homes have a few extra blankets or comforters that can be tossed on top of the tank. Nothing too fancy, the more the better.battery-powered-air-pumps.jpg

Battery-powered air pumps can be very cost effect ways for providing aeration and water current to your tanks. I happen to have the Penn- Plax “Silent Air” Model B11 which uses two D batteries. It can typically be purchased for about $11-15 on-line. This unit has a very useful feature: it will not turn on until it detects the AC power has gone out. If you’re expecting a storm in the night or perhaps expecting a storm and you have to leave the house for some reason, it is very easy to add one or two of these to your tank. If the power does not go out they never turn on. But if it does go out and you are not around, they will buy you some time until you can get your plan in place. I would suggest using a minimum of at least one unit for every 2 feet of tank length for most standard tank sizes.

When using battery-powered air pumps (or even normal AC air pumps on a UPS unit) don’t use an air stone or wood block. Simply run the tubing to the bottom of the tank. Rigid airline tubing works best but standard airline can be used. In either case you may need to add weight to the hose to keep it in place. I use a rubber band to attach the hose to my cleaning magnets and drag the magnet to place it where needed. The large rolling air bubbles will create surprisingly good current and water surface agitation for gas exchange. I’ve found large rolling bubbles to be much more effective than the fine mist of bubbles produced by stones or wood blocks.

The Penn-Plax “Silent Air” Model B11 unit that I have uses two D size batteries. The unit will also run on a single battery but will obviously not run as long. In my tests running the unit on two D batteries the Model B11 unit last just short of 5 days of continuous use. I was very impressed with this. A unit like this is a must-have for every person with an aquarium.


DC/AC power converters (sometimes called “invertors”) are inexpensive and flexible devices often overlooked by reef hobbyist. Converters that will power 400 W (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 better yet marine batteries used on boats or even directly to a car via a cigarette lighter port if you can park within an extension cord distance. These are ideal for running a heater and a powerhead or two. It can also be used for recharging a mid-sized UPS unit if you can’t get the car close enough to the tank. DC/AC power converters are really your only cost effective way for running a heater. Typical aquarium sized heaters in the 100-300 W range will drain just about any UPS unit in a matter of minutes. Obviously, a generator would be ideal but they are priced beyond the reach of many hobbyists and tend to be in short supply when you really need one. If you do hookup a DC/AC power converter to a running car be smart about it: put the parking break on, do not run the car in the garage (deadly fumes) and make sure nobody drives off with your car.

The DC/AC converter also comes in handy for non-reef related items such as road trips and camp outs. My 400 W converter was plenty for running a small TV and a DVD player for my daughter.

The unit I use runs cool to the touch, is very quiet, can easily be converted from cigarette lighter to battery terminal feed. It has a 20 A (ampere) fuse with two power outlets and a master on/off switch. The unit weighs less than a pound. I’m really impressed with it.

Uninterruptible Power Supplies (UPS) and generators are pricey items. In most cases a generator will be recommended over a UPS. A UPS is typically used for computer systems to protect them from sudden power outages. Most people have fairly small UPS units designed to run the computer for only a few minutes – just long enough to power down the system safely. These smaller UPS units will likely be a waste of money for most aquarium hobbyist. Larger (and expensive) UPS units may have some use in the hobby. However the costs are in the same area as entry level generators which make it hard to recommend them. If you happen to have one handy use it. If generators are not an option based on where you live then perhaps a large UPS unit in conjunction with a DC/AC converter is your best option.


How do “on-line” UPS’s work?

On-line devices offer stable power output but are usually more expensive than their near-line versions. An on- line unit contains a rectifier that converts the AC coming from a wall outlet (nominally 120 volts) into DC voltage, which it then uses to power an inverter. The inverter changes the small DC input—typically something like 48 to 60 volts, into a pure 120-volt AC to power the output load. The initial conversion should remove power-line anomalies and fluctuations, and the inverter creates a near-perfect sine wave. The batteries are used only when the AC power is cut off; then the UPS powers the inverter through a DC-to-DC converter that raises the 48V bus to 120V. The rectifier and DC-to-DC converter are connected in parallel, so no switching is necessary to go from AC to battery power.

Another drawback of a UPS unit is battery life, not only in terms of how long it will last when the power goes out but how long the batteries will last before they need to be replaced. It is common for batteries to need to be replaced after 5 years of use. It may be less expensive to purchase a new unit instead of replacing the batteries. This is yet another reason to consider a generator instead.

In selecting a UPS unit you should know a few facts. There are two main types of UPS units: on-line and near-line (also called line-interactive). With on- line units your equipment is always running off the battery and the battery is always being charged. Near-line UPS units run the equipment from standard household electricity and switch over to battery only when the power spikes to high or drops to low. Many near-line units can provide some filtering of the power without switching over to battery. For example, my UPS unit will deliver acceptable voltage to appliances plugged into it when the line voltage is between 103 to 130 volts. A house with ideal current will run at 115 volts but fluctuations between 110 and 120 volts are common. On-line UPS units effectively filter input power and provide a constant power source (see side bar “How do on-line UPS’s work?) but have reduced battery life. These are great features for sensitive equipment, not really needed for power heads and air pumps. Weight can be a serious issue for some of these units. My 3000 VA unit weighs in at just under 180 pounds. I have it on a board with casters so I can move it around. Noise and heat can also be (minor) issues with UPS units. The inverters can be nosy and generate a bit of heat if keep in a small enclosed space, such as a walk-in-closet.


Generators are the best all-around option for long-term power outage survival. Like anything, generators have a large number of trade offs that need to be considered before selecting a unit.

While preparing this article I tested several UPS units ranging in size from 450 VA to 3000 VA. I tested them running a MaxiJet 1000 power head (20 W) and then retested with a Whisper 600 air pump (3 W.) I fully expected to find a decent sized yet affordable UPS the people might consider using. After looking at the cost versus how long the units were running, I decided to stop the testing. No UPS unit could be recommended after I saw the Penn-Plax “Silent Air” battery powered air pump last nearly 5 days. Even the largest UPS unit I tested could not run an AC- powered air pump half as long.

In selecting a generator, the most important thing to determine is what capacity generator you need. There is nothing worse then buying a generator only to discover during a real emergency that your generator is under-sized. James A. Fox wrote an excellent article (http://www.advancedaquarist.com/2002/3/short ) that covered how to calculate the electrical costs of running a reef tank. In that article, James shows how to determine the current needed to operate your tank. This would be an excellent start in determining how large a generator you need for full-bore, business-as-usual operation of the system. In a time of crisis, the tank might be able to survive with somewhat less power than usual. For example, your corals will live for a few days under reduced light output. Also, please remember that in a time of power outage, you way want to run other important electrically powered equipment in your house as well. Many modern heating systems are absolutely dependent on AC power to deliver heat to your house. You may decide that eating food is nearly as important to you as your reef aquarium, so budget adequate power to run refrigerators, freezers and appliances used for cooking.

In general terms a basic generator consists of four major components: the engine which provides the mechanical power, the alternator which is attached to the engine and turns the mechanical energy into electricity, an output/control panel [which provides a place for the electrical outlets (receptacles), circuit breakers, and controls (switches)], and a metal frame to hold the whole thing together. In addition to these four major components, there may also be a fuel tank separate from the engine and often mounted on top of the frame.

The engine is the heart of your generator. The primary concern with the engine is the type of fuel it will run on. (see below). The second thing you need to think about is the brand name. There are many companies making generator engines. There are a number of trades offs with engines involving life expectancy, noise, ease of service, etc. Choose a name that you know and trust, and for which you can obtain service in your area.

One of the largest choices regards whether you need a manual start or an automatic transfer switch (ATS). Most of us can only afford the manual start option (you get to the pull the string or push the button). However, more affluent aquarists with big tanks or people looking to protect more than just the reef tank such as boiler (for heat), refrigerators (to protect food), some lights, etc may want to consider the automatic transfer switch. The ATS system is just as it sounds. Within seconds of detecting a power outage the generator starts and switches over to provide power and will disconnect and power down when service is resumed. Some of the nicer units include a plant exerciser feature with the ATS. The exerciser can be programmed to fire-up the generator at set intervals (monthly, weekly, etc). This will keep the starter battery charged and keep the unit in top working condition. These systems may also monitor coolant, gas-levels, operating temperature, etc.

Even with the manual start generators you have a few options available. One is the Manual Transfer Switch (MTS) for the folks who want to be rich but can not afford the ATS system. The MTS is hardwired to the house wiring but instead of an automatic switch over the switch is manually used to link the generator to the house.

A major advantage to both ATS and MTS units is that they may be able to run the entire house, albeit perhaps at a reduced energy budget. This means that your heating system will probably continue to function, and modern electronic- ignition kitchen ranges will still be available for cooking.

For the rest of us we have the stand-alone generator that is often seen at home improvement centers. These are often entry-level generators and may be all that you need to protect only your reef tank (provided you are home to start it). Don’t forget to have some dedicated extension cords handy. You don’t want to be searching for them when you need them. It may be possible for you to keep your heating system running with a simple stand-alone generator and a medusa of extension cords, but the requirements for that task fall outside the scope of this article. Given the capacity of most stand-alone generators, it will probably require a lot of leg-work, switching various loads on for short periods of time so as to maintain some level of function without overloading the generator.

One also needs to keep in mind that generators need to be serviced and tested at least monthly (weekly would be better). You should run the unit for at least 30 minutes and cut over a few appliances to make sure everything works as expected. It is not uncommon to have a power outage on a dark stormy night only to find out you are out of fuel. After getting some fuel from the garage you find out the starting battery is not charged (if you have an electrical start). If you have a manual recoil start (pull string) hopefully it decided to start up on the first try. Otherwise it will be like the old lawn mower, weed whacker or chain saw… pull, pull, pull, pull, ouch… my back hurts.

The next major item to consider with a generator is the fuel source. You have basically four options: gasoline, diesel, natural gas or propane. Each one has tradeoffs to consider. (See table below). In most cases gasoline powered generators will be your best option.

GasolineDieselNatural GasPropane
Easily obtainedHighly flammableLeast flammable fuel sourceLarge storage tanksRefueling not necessaryLower power output (30% less BTU’s per unit than gasoline)Long shelf lifePressurized cylinder of flammable gas
PortabilityShort shelf life (approximately 12 months)Easily obtained18-24 month shelf lifeClean burningHigher installation costClean burningComplicated fuel system (increased possibility of failure)
Least Expensive Generator TypeStoring large quantities is hazardous InefficientOn site fuel delivery availableMay not be available during power outageAvailable during power outagesNot available in many areasEasily stored in both large tanks or in smaller 5 – 10 gallon cylindersHigher installation cost
Gas can gum up in cold weather. May not start at all.Can be hard to start in cold weather.No storage tank neededFeed may be disabled during  natural disasters.Obtainable during power outages

The location of a generator is a great concern. It would be very unwise to attempt to run a generator from your basement. All internal combustion engines produce carbon monoxide (CO) gas. The CO gas can leak out of the engine exhaust system into your house. The fact that a generator is likely being used during bad weather when your home will be sealed up tight makes it suicidal to run a generator improvisationlly placed in your basement. It is unfortunately not at all uncommon to hear about people requiring hospitalization or dying from CO poisoning from running a generator in their basement. If the basement is your only option, seek out advice from a local fire inspector to see what building codes you may need to consider. The technical requirements are similar to putting a hot water heater or boiler in your basement. Noise and heat can also be concerns with a generator.

If you plan on hooking up any sensitive electronics to a generator be sure to use a U.L. listed surge suppressor . Many generators generate power clean enough for power tools and other construction tools but the voltage variations can cause damage to voltage sensitive appliances such as computers, TV, entertainment systems, etc. Always use a surge protector.

Fighting off a power outage during the winter months is about as difficult as outages can get. Besides the loss of power you typically lose your household heating. Not only is this an issue to your family but it is a serious issue to your aquarium. Luckily you and your family can put on sweaters or jackets for a few hours if needed. The aquarium on the other hand it’s not so easy. It will be unlikely that you can maintain tank temperature higher than about 15-20°F above ambient room temperatures. Most reef keepers use a temperature range of 78-84°F. You should be able to maintain this temperature range with a typical aquarium heater and DC/AC power inverter provided you can keep the ambient room temperature above 60°F.

As soon as you lose power during the winter months, I would suggest that you immediately try to conserve tank temperature by moving heaters from the sump to the display tank, provided you have at least a DC/AC inverter and a few battery-powered air pumps. Use at least one air pump per two feet of tank length. (They are sufficiently inexpensive that you can use more than this.) Once the heaters and air pumps are in place the best way to conserve temperature is by using foam insulation sheets (thicker is better), which can be found at most home improvement centers. Use one sheet for each side of glass, and ideally one for the bottom and top of the tank too. Then cover with blankets and towels. This will be about the most you can do. Sit back and hope for the best. Monitor the tank temperature every 30 minutes or so.

If the tank temperature drops below 72°F you are seriously pushing the limits of many critters in your tank. If you have access to a gas stove, heat water and use 2 liter soda bottles. In a pinch you might consider heating tank water itself and slowly pouring it back in. Even if you’re one of the lucky few with a generator, you will likely still face issues with falling tank temperatures due to falling room temperature.

Portable space heaters can used to help keep the room temperature above 60 F. Your only option for space heaters not needing electricity may be kerosene heaters. Kerosene heaters provide not only heat but also some light to the room. However there are some substantial risks associated with kerosene heaters that you should understand before using them.

Before you purchase a heater, make sure your local building and fire codes permit its use in residential structures. Then check with your insurance carrier to determine what impact the use of these heaters may have on your homeowner’s policy.

The basic design of a kerosene heater uses a wick to draw the kerosene from the fuel tank to the combustion chamber. Most modern units include a device to ignite the wick and an automatic tip-over protection device designed to extinguish the wick if the unit is turned over.

Be sure to use the correct fuel! In researching this article I was amazed to see how many people have died because they used gasoline instead of kerosene with a kerosene heater. For the vast majority of units the proper fuel to use is certified 1-K grade kerosene.

If you ever used one of these heaters, you know they can really get hot. According to manufacturer’s literature, the operating surface temperature of these units can be over 500 F. Be sure to keep it at least 3 feet away from any potentially flammable objects. See the references section for an excellent article on safety concerns using a kerosene heater.

In summary, if you are able to maintain a room temperature of 60°F, have at least a DC/AC inverter strong enough to power the heaters you need (a generator is ideal), and can provide enough circulation to the tank via battery powered air pumps (or power heads on a generator) you should be able to handle an extended power outage.

There are many natural indicators in our tanks. Many organisms are adversely affected by abnormally high or low temperatures and low dissolved oxygen. During a power outage, your primary indicator organisms will typically be your fish. They are often the first to die. The corals are hard to use as indicators but if you see your bristle worms coming to the surface of your sand bed things are getting pretty bad.

As with any disaster recovery plan, don’t wait for the disaster to find out if you’re ready. Try a few test runs on the weekend to make sure your plan will work.



  1. http://www.howstuffworks.com/emergency-power.htm
  2. http://www.howstuffworks.com/question28.htm (How a UPS works)
  3. http://www.howstuffworks.com/category.htm?cat=Powr (Many articles on power)
  4. http://www.best-power-generators.com/ (retailer, with well done FAQ’s)
  5. http://www.utilityfree.com/ (alternate power sources such as solar)
  6. Electrical Power: Motors, Controls, Generators, Transformers, Joe Kaiser, ISBN: 1566373662, Jan 1998.
  7. http://muextension.missouri.edu/xplor/agguides/agengin/g01999.htm (Portable Heaters)


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