you know the dimmer swicth idea has crossed my mind and may be the way to go for now. i have the tank insulated right now but its done with cardboard which gets the job done for now but will be switched to foam board as soon as i can get it. i need the insulation to stabalize the temps, it had alot more flucuation before i put the cardboard on. the problem is its getting into the 95 degree area during the early to mid afternoon then dropping to 83 at night (hot side temps) so i think that dimmer will work till i can get a t-stat.