I would try it first. Remember they need a hot "spot" of 90-92*. It may work just fine. The heat will travel the glass very well too and will heat a much larger area than the pad itself. It will gradually cool off away from the pad. I would put it in the middle of one half of the tank bottom. Give it a try before ordering something else. Leave it on for about 24-48 hours and check your temps, you may be surprised