Who Gives A Fish Forums

I'd also check the wattage. Two 200W might be overkill for 75 gallons unless your room's really cold. What's your ambient temp?

Keep 'em away from the substrate too. Sand can trap heat and mess with the thermostat. How often you cleaning your heaters?

I just put mine wherever, but now I'm worried. Gonna move one to the other side. What's your water change routine?

Opposite sides works best for me. Also, consider a heater guard if you've got curious fish. Mine like to nibble at everything.