I use 2- 300 watt heaters on my 200 ... Eheim Jager in tank and a finnix titanium in the sump.. Its in the basement ambient temp is 75-77 F and tank is kept at 82 F, (glass tank)
In my 150 I use a titanium 500 watt in the sump and a 300 w fluval E in the tank.
This tank is kept at 85 F , same ambient temp. (acrylic tank)
Upstairs I keep my house cool, ambient temp is 71% , tank is in cold location
(near window) . Its a 90 gallon uses 2- 300 watt heaters to maintain 82 F. ( glass tank)