You would figure with less water in the sump, less heater wattage would be needed. Thanks for the reply. Sounds like overkill, but
I think i'll start with 200 watts and see how long it takes for the main tank to reach the set temp, and then go from there.
If anyone is interested in what i find, let me know and I'll post results in a week or two.
Thanks again aaxxeell for the reply.