@Premier-Point0 We set ours to about 32°C (90°F) from opening day, usually around mid-March, to closing day, often by late October or early November. Our pool is "laguna" style (3 overlapping circles), deep end is 6' and in full sun most of the day. Dark blue 'wave' liner - helps to warm the water. Vertical walls are all with at least 4" of outdoor proof insulation (foam) - reduces lost heat into surrounding ground. The cold nights and months, a solar/lunar blanket is used. During the summer, it is left uncovered - easy for guests to use any time of day or night. The heater is on from about 7am to midnight. Almost no guest use it out side those hours - during warmer months it only drops a few degrees anyways. We are located near Windsor, Ontario (Canada) / Detroit, Michigan (USA).