WOW! I was doing a water change in my Red Sea XL525, when I thought I smelled something hot. Went upstairs to get my wife as my sniffer ain’t all that good. She came down and said she smelled something too. Looked all over. Decided it was nothing and went to open the window to vent, then close up and recheck. I had checked every plug on all my other tanks, nothing hot. I have three tanks tied together to a sump for a QT system by the window. Decided to check the heaters and this is what I found. We leave in the morning for the weekend. I have had nothing but problems with finnex heaters. Could have come home to a burned down house.