Aquarium Electrical Systems

Electricity and saltwater do not mix well; nevertheless we aquarists need to use a lot of electricity to run our systems, so safety is something that should always be kept uppermost in our minds. Putting power strips and ballast transformers under a tank can be a costly mistake. You only need one leak, a few drops of saltwater, and some of your equipment may be ruined or even worse, cause a fire. Another issue that should be considered is your tank's effect on your power bill. In this case, aquarists need to think about efficiency, because the more efficient something is, the less power it will use. We will want to concentrate on things like pumps that run 24/7, as well as high power lighting systems that may run many hours a day.

Understanding Electrical Power

Power is what makes your meter spin and is calculated in watts. To determine how many watts a device uses, look for the amount of current it draws. This will be rated in amps. To calculate power, just multiply the voltage the device uses in volts by the current it uses in amps. Most of the things we use run on 120 volts AC (VAC). If we have a 120VAC pump that draws 3.5 amps, then it consumes 420 watts of power. To convert this to cost, you will need to multiply the instantaneous power by time. Your power bill is rated in kilowatt-hours (KWH). Our pump that draws 420 watts uses 0.420 KWH every hour, 10.8 KWH every day, and approximately 312 KWH per month. If the power company charges \$0.06 per KWH, then the pump is costing us \$18.75 per month to run. (((120 X 3,5) X 24 X 31) / 1000) X 0.06 = 18.75. Now that we can figure out how much a device is costing us to run, we can compare different devices to pick the one that will cost us the least to run. If we look at the pump that draws 3.5 amps and pumps 2000 gallons per hour (GPH) and compare it to another pump that pumps 1800 GPH and draws 3.3 amps (((120 X 3.3) X 24 X 31) / 1000) X 0.06 = 17.68 we can see what the cost difference will be. An easier way to look at this may be to compare amps to GPH, because they both run on the same voltage and for the same amount of time per month. That is 2000 / 3.5 = 571 GPH per amp and 1800 / 3.3 = 545 GPH per amp. This comparison shows that the 2000 GPH pump moves more water for the money (26 GPH per amp), than does the 1800 GPH pump. The 1800 GPH pump costs less to run for the month, but it is less efficient. Differences in efficiency may be more apparent on ballast transformers. The ballast also has an amp rating. A 250 watt MH ballast that draws 2.6 amps at 120 VAC is drawing 312 watts in, yet producing 250 watts output. The 62 watts difference will be turned into heat. A different 250 watt MH ballast that draws 2.2 amps at 120 VAC is drawing 264 watts, so only 14 watts will be turned into heat. The 2.2 amp ballast transformer may cost more to buy, but you can work out the monthly cost as was done for the pump, and you will be able to determine how long it will take to save the cost difference.

GFCI Outlets and Your Aquarium System

It is my belief that all aquarium equipment should be on GFCI outlets. A day may come when a GFCI may save your life. Get a good one that replaces a wall outlet. It will have a line side, and a load side. The line side connects to the wires from the breaker panel, and the load side connects to the rest of the normal outlets on the circuit. The GFCI outlet also protects the outlets that are on the load side. When GFCI outlets get old, they tend to trigger easily. If you have one that does this, replace it so that it does not trip and shut your tank down. You may want an electrician to install them for you, so that you don't get shocked trying to protect yourself.

Notice: If you are not completely comfortable working with electricity, then for your safety, and that of your family and tank, get a professional to wire it for you.

Constructing an Automatic Top-Off System

A float switch can be used to run a powerhead in a water container, or a solenoid valve on an RO/DI system, or an elevated storage tank. Set the float switch to the normally closed (NC) mode. When the water level in your sump goes down, the float switch will close, which will cause your top-off pump or solenoid to run until the water raises enough for the float switch to open. If you are using a container of top-off water with a pump or powerhead in it, then it is a good idea to put a second float switch in the container, so that your pump or powerhead does not run dry. This float switch should be set to normally open (NO). To change the float switch from NC to NO just remove the plastic clip on the bottom of the switch tube and slide the float off, flip it over and put it and the clip back. That is all that is required to change it. I drill a hole in the center of a PVC pipe cap for the top of the float switch and wires and four small holes for vents so the assembly does not get air locked. Don't forget to shut down your automatic top-off device when you are performing water changes to your tank.

Parts List:
Solid-state Relay NO with a 3 - 32 VDC coil and a 120 VAC @ 3 amps
Full wave bridge rectifier
2 K ohm 1/2 watt resister
Three wire power cord
Float switch Grainger 2A554, McMaster 50195K65
Duplex outlet
External duplex outlet box

 Float Switch Float Switch in a 1 1/4" PVC pipe cap. (inside) Float Switch in a 1 1/4" PVC pipe cap. (outside)

 Float switch setup for the RO/DI container to protect the pump from running dry. Float Switch setup for the tank with a PVC coupling with a 1 1/4" X 1" FNPT bushing and bulkhead strainer so no snails or fish can push on or jam the float switch.

Constructing a Low-water Pump Shutdown System

A float switch can be placed in your sump so that if the water gets too low, the circulation pump will be shut down. This can solve two problems. If the reason the sump is low is because there is a leak somewhere, then it is best to stop pumping water into it. Also, it will protect your pump from running dry. The relay will handle a load of up to 3 amps. This is enough to carry a fairly large pump. If your load is larger, then use the alternate relay, which is good for up to 10 amps. You will want your float switch set to normally open (NO) mode. If the water level in your sump gets too low, the float switch opens, and the circulation pump stops. The reason this design is more complex than the top-off is because we don't want the pump to be restarted from water that siphons back from the tank, as this would cause the pump to turn on and off. It could do this repeatedly for quite some time, causing damage to the pump. The reset circuit will prevent this from happening. To restart the pump, simply press the reset switch.

Parts List:

Solid-state Relay NO with a 3 - 32 VDC coil and a 120 VAC @ 3 amps
Full wave bridge rectifier
2 K ohm 1/2 watt resister
Three wire power cord
Float switch Grainger 2A554
Duplex outlet
External duplex outlet box
Push Button

Using X10 to Control Electric Devices for Your Aquarium

Places to get the components for these projects:

Float switches:
www.mcmaster.com

Solid state relays:
www.hosfelt.com You will want relays that are normally open (NO) for these projects.

Electronic Components:

X10 modules and controllers:
www.x10.com X10 plug-in modules
www.hometech.com Wire-in Levaton X10 products like phase bridges, X10 wall outlets and wall switches.

Photo Credits:

All photos courtesy of Jon Garner.

Disclaimer:

Construct these projects at your own risk. The author, Reefkeeping Magazine and Reef Central will not be responsible for any damage or injury caused by improper construction of these devices. The combination of electricity and water can be deadly, so please use common sense or consult a professional electrician if you do not have the proper experience.