1 ill g;3381036; said:i see... so like a 400 watt heater in a 45 gallon sump is fine?
it wouldnt get too hot in the sump?
As previously mentioned... provided you have proper water circulation...
Regarding heating, look at your tank and sump as one body of water... because they are...
2~3W per gallon is sufficient under typical conditions... (air 68*F or warmer, water around 80*F)... Therefore 600~850W should be sufficient...
If you do not have proper water circulation, you may have heating issues, and the solution is to increase water circulation...

