I did and came up with a solution. I cut a 10 inch wide piece of 1/4 inch acrylic to about 2.5 feet. I then took out my propane torch and made some bends, they fit the rim of the tank and the lower area that holds the bottom of the heater. I cut another 10 inch wide piece to 2.5 inches; this piece holds the top of the heater out of the water. A little Weldon 14, drill and tap, a couple of nylon screws and the suction cups from one of the heaters and I was done. I did not take any time to make it look pretty, heck it is going in the sump.
I was tired of the suction cups coming loose and the heaters rattling around the inside of my sump. Or needing to make an adjustment and the knob was to wet from the heater being under water. It looked terrible and could not be good for the heaters, rattling around.
The project took about 2 hours, watching the Weldon dry seemed to take the longest.
