My heater goes on and off due to Cell Temperature and not Water Temperature. For example, my spa is 88-degrees, I set the desired temp to 102-degrees. The heater comes on until the Cell Temp is 102, which takes only a few minutes, and then shuts off until the Cell Temp drops below 98-degrees. During this heat cycle the water temp may gain only one or two degrees. So it takes a long time to get the Water Temp up since the heater is working off Cell Temp. How do I get the unit to run off Water Temp and not Cell Temp? Where is the Cell Temp sensor located? I have an 18,000 gallon in-ground, salt water pool with a spa. The pool is controled by an Aqualogic controller and has a DE filter. The Kreepy Krawley seems to work ok and the unit shows "flow".