I have a 15ft round above ground pool , i guess around 5300gal. And like years past , its so frustrating opening a my pool to crystal clear water that is so cold and having to wait for weeks for solar cover to warm it...So this year im finally getting a heater !, just not sure it whats needed... Im pretty sure i want a natural gas heater. Been reading reviews on solar panel heaters and they just seem ineffective... Would like to set the desired temp , possibly 24hrs later be warm... Im in Chicago so i think gas is the best option.. i wish there was just a electric only plug in heater unit because my gas meter is in my basement 75ft from my pool pump..... Any suggestions on btu size and brand of heater would greatly be appreciated. Most likely will be buying heater from American Sales ,thats really only local pool store around.... Thanks again guys this forum kept my water chemistry perfect all summer long