I actually had that issue for a while, but I finally got it fixed when I downgraded my return pump. After much testing (power kills, back-syphon testing, etc.), I am confident that the water level in that chamber will remain high enough to keep my heater covered as long as I keep up with my top-offs! Thank you, though! If that chamber runs dry, I'll probably end up with a burnt out pump, busted heater and a huge mess considering the only way it should happen is if the syphon on my overflow was to break...... *shivers*You may want to move your heater, people don’t suggest putting it with the return pump because that chamber can run dry