We just opened our brand new 20x40 inground vinyl pool. Pool builder tells me that the pool is 26,000 gallons. We have the Pentair 125,000 Heat/Cool pump. Current water temperature is 66 degrees and we want to get it to 80 by Saturday. The daytime temperature is forecasted to be 75 degrees for Thursday/Friday. Morning/overnight temperatures are around 45 degrees. We also have the automatic cover so hopefully that will keep most heat in. Based on lower temperatures at night and morning, I was thinking of just running heat pump from about 9am until evening. With this being my first experience with a pool and heat pump, I have no idea what to expect. Is it even possible for the water temperature to reach 80 degrees over the next 48 hours with those ambient air temperatures? I wasn't sure if a heat pump has the capability to get the pool water hotter than the ambient air temperature is outside. I realize there is a probably a lot of math to this question but would appreciate any insight on how to calculate this.