Okay, I've decided to attempt this flexwatt idea. . . although I'm a little nervous at setting it up. How much do I need for a tank 48x18x18 (lwh)? Also, I've read about people using a dimmer swith temporarily, then switching to a thermostat. Is this a good idea, and if I do it that way, how do you hook the dimmer in line with the flexwatt?. . . I think that's all the questions I have for now, but there will be more to come. Can anyone help? Bye the way, I'm housing corns, and the tank is divided down the middle 24x18x18.