I have a 40x18ft roman style pool with an 8ft deep end, there is a 5x5ft hot tub attached. I have been told it is about 28K gal total. We live in south TX 10 miles from Mexico with a ambient temp 90+ deg days from mid April until Sept. There is no gas to the site. We would like to have a hot tub that is actually hot (100deg) at times, doesn't need to be all the time. In addition it would be great to have the pool 80-85 deg in the "winter" when ambient temp is 50-60 deg. I do not have a cover because we have a Catch-a-kid pool net (and having both would get very cumbersome to remove) but if push comes to shove I could get one. Would a heat pump work for this and if so what size? or will I have to get a pool heater?