What fish are you keeping?
And what is the temp gap between what these potential fish need, and room temp?
As an example, when I kept haitiensus and Alcolapia, I had a 10' temp gap, because haitiensus and Lake Natron cichlids like temps in the 80s, so I kept 3 x 200 was heaters in their 6 ft tank, room temp low 70s.
For Uruguayans, and northern Mexicans like H carpintus, room temp was fine year round.
For Lake Malawi cichlids, where the average lake temp is mid 70s, a single 150 watt heater was sufficient in winter,and I'd unplug most heaters in summer (except in the haitiensus tank).
