Planted Tank Guru
Join Date: Nov 2009
Location: Missouri united states
I have a couple ten year old Hydor Theo 400 watt heaters from Discus day's and noted that dial on the heater is often way off from actual temperature as read on tank thermometer.
Right now,I have one of these heater's set just a click above off ,and it maintains 75 degree F according to three different thermometer's.
If I set the dial on heater to 75 /78 degree's F the water warms to near 82/84 degree's F as per thermometer reading's.
I just need to keep an eye on thermometer when adjusting temps rather than dial on the heater itself.
Some consider the Hydor's junk ,but they are still working albeit as described, for the last ten year's.