I was wondering what would generally be the best size of flexwatt to use on 20-55 gallon aquariums? I know that they make the 11" stuff and that is what I was thinking about getting to cover a small portion of the aquariums. I also have some roach colonies that could use some of that on the bottom of the containers. If you get flexwatt do you need to buy a dimmer or thermostat or are they unnecessary? I know that many people say to get a dimmer with it, but that would almost be as much as a normal uth for a piece of flexwatt, dimmer, connections, and cord.