Just adverted disaster. Luckily I got home from work early today and went to check how the protein skimmer was doing. When I looked under pump I smelled a burning smell. After looking around frantically for a few moments I noticed the Return pump area way low. The heaters were out of water and on. The temp sensors are where the protein skimmer is. Not sure why they were on but it was on long enough where the black coating on temp holder melted to the Cor-20 cable. I was able to pull it off. Looks like the ATO pump died so just amazon primed a new one and now looks like I need new heater or heaters
So I didn't see anyone chime in about your heater placement on here, but you should never put the heaters in an area where the water level isn't constant or at least cant go down that far. The best place you could put them is the skimmer area as that area should never change, at least it wont go lower than the baffle. Just think if your sump was all acrylic you could have melted a hole in it or maybe even start a fire from the melted plastic.