I noticed something last night with my heat pump...granted, outdoor temps went down to about 55 and I know heat pump efficiency and output reduces as temps drop, with about 50 being the lowest it will operate...but the pool was 76 at 6pm last night. This morning, with the heat pump running all night, was, well, 76. Didn't gain even a single degree. But I'm thinking I lost a lot of heat overnight, and maintained temp at least. Had it been off, I easily would have imagined a 3-4 degree temp drop. Does this sound right? The heat pump seems to do it's job as I expected, as I know it's not a heater, and is a slower process. So just checking really. I have no errors or anything on the control panel, and flow is strong...thanks.