Heater placement?

[16fishes]

Where’s the best place to put a titanium heater in a 25 gallon lagoon?

 

[Tangdora]

If your tanks had the built in sum on the back any chamber will work. But would avoid the final return chamber where evaporation can cause the water level to drop exposing it to open air. If that’s your only chamber that does not have media and filter then just put it there but don’t let it run dry