Smallest heater for a 30g

[Joe5688]

I've got my sw tank up and running and I currently have a 100w heater. Problem is that it never turns on. My tank stays between 80.1 and 80.6 all day everyday.

I would like to take the big heater out and put a really small one in my ac50 hob refugium. Do you think since my temp never changes that I could go with one as small as a 25w or 50w?

 

[Rgillund]

I don't use heaters in any small tank. Including my sps heavy Solana. I have had to many heaters malfunction and stay on. Unless you have it plugged into a controller its not worth the risk.
If you really think you must have a heater then use the smallest one you can find so when (not if) it fails you will have more time to catch it. I know a few reefers who don't use heaters. Usually room temps along with equipment will keep temps plenty stable

 

[Joe5688]

Yeah my room is usually 76 and the heat from the pumps and light seem to keep it in the 80s.

 

[Joe5688]

How many degree difference would cause problems in an aquarium?