Originally Posted by SlimStretch
I'm new to the aquarium thing, I tried searching the site for anything on heaters but I couldn't find anything.
What do i need to know about a heater before buying?
How do the heaters work, Some have a set temperature? Others how can you tell what temp you have set it at?
Generally you need about 3-5 watts per gallon. I don't care for the preset ones as they never seemed to keep the temp right. Look for an adjustable one which will have a knob with the temp settings on it. You'll need a separate thermometer such as the glass submersible ones like this PETCO Thermometer with Suction Cup at PETCO
to check the temp of the tank. Often you'll find that the temp you set on the heater is off from what the thermometer reads. It seems a lot of heaters are like this so make sure you use a thermometer to confirm the temp. I like to place the heater near the outflow of the filter so the heat gets evenly distributed and place the thermometer in an opposite corner furthest away from the heater.
Nice features to look for on heaters are an indicator light so you know when the heater is operating and an auto shut-off that helps prevent heater failure if the water level drops below the heater (such as during water changes).
Hope this helped some.