what size heater needed for large tanks??

[congofeet]

I once had a heater malfunction and my tank got up over 90 and all the fish made it. I realized the heater was broke when I opened the lid to feed and I got a hit of very warm air. I had a goldfish in the tank and he changed color after the incident (from silver to gold). He actually still lives happily now in my 135 gallon tank and is about 9 inches long now.

 

[scubasteve06]

Multiple heaters at lower wattages are always best.

 

[jay240G]

i agree with congofeet i have 240 and uses 400w total and stays very steady, also never had any heating problems