hey, up until now ive used marineland stealth pro 300 watt for my 90 gallon piranha tank, however they run into the damn thing, alot... this morning i found my tank at 72 degrees, 8 lower than normal, with the heater light on, but no heater coming from it. I think they finally did the pathetic thing in. What GOOD heater can I buy that will resist the battering of a piranha, and will heat my tank properly with only 1 heater. thanks in advance