My basic question is how expensive will it be to heat my pool. Considering purchasing a new heater to replace to currently broken one unit. I open in mid May but usually don't get in until mid June. Close in mid October but rarely get in after school starts early September. The wife wants to get in early May and heat it up for the occasional pool party. It averages about 82 degrees mid summer months. I would like to heat it up to about 85-88 on cooler days. The plan is to get a raypak 406,000 propane heater. I'm confused about calculating how much propane it would use and would the existing propane tank which is 100 gallons be big enough or will I be refilling often. If any out there has the raypak, I would love some feedback on it or any other recommendation would be appreciated. Propane price in my area right now is 2.99/gallon.