The pool heater is on. Set at 83. Pool temp is 83 and has been 83 all week. On the menu select is suction temp actual 52 f. What is this ? I called pentair pro technical and asked him. He said its actual water temp coming into heater. But how can that be if water temp says 83. He said the bottom of pool water is colder. I started thinking and the pool is sucking from top of pool. Out came the book but I can't find any info. Says call a pentair tec. What is this ?