Oversized heater, what risks?

[fr3n0z]

Hi guys, I am going to build a 80l (20g) total (sump+ display) I've found a cheap second hand aquamedic 200w heater with thermocontroller.

What are the risk in running a 200w heater on a 20g system? I think is double the watts I should use.

 

[blaxsun]

None, other than if it ever gets stuck on you'll cook your tank that much faster.