So I heated my pool on Sat to 86, then turned it off Sat night. Wake up Sun morning to 81. Then started heating on Sun afternoon to 86. Turned it off Sunday night. It has since been constant at 81. I would expect at least a degree here or there. If I start heating the pool, it starts going up. If I use the spa, it seems to be working fine. This is in Houston, TX. It's been in the mid to high 70s, occasionally going to low to mid 80s. Do you think there could be a problem with the temp sensor or something else? Just to clarify, my concern isn't the temp going down to 81. It is the fact that it's been 81 for hours now. I have never seen water temp stay constant for so long.