Yes! I wouldn't let it touch the plastic but why not! I would think it would be better in the wet dry or refuge or what ever you have but I dont' see why not if it fit but my over flow boxes aren't big enough for a heater and I have a 135 gal. tank w/ two OFB and I don't think a heater in there would be sufficent enough to heat the tank and you would probably need 1 250 watt w/ a 75 gal. tank