zcpetty
So I'm looking at 5 gallon tanks.. I have a spare preset aqueon heater that is 100w.. is this too much? Its the fully submersible small sized one.
That is WAY to big. You need a 25 watt heater.
What is the ambient temps of your room versus the heat you want the tank at? Either one will work and will not harm anything - if anything its overkill but it shouldn't turn on unless the temps get below 78 on the preset. Do you have a thermometer to measure the temps for accuracy?
If you are going to buy one, its best to get one that is adjustable in case you need it someday ( in the case of ich, etc )