Hey Everyone, I'm somewhat new to the forum, I usually stick to searching to find what I need to know. Such a huge inventory of knowledge on this board, but I didn't have that much luck this time around. It seems everyone just says to go with a large 406 BTU heater. The pool without a heater sits around 76-78 (to cold for me) throughout the summer (located southwest CT) and we don't swim often, so i don't expect to use it often, though we have a new addition to the family who will prob use the pool more when she is older. Its alos not fun having guests over who feel the pool and go "Expletive no, way to cold". i feel like I'm nickel and dimming, but was wondering if i will truly see a noticeable difference between the Raypak PR266AEP and the PR336AEP. The increase in BTU's seems pretty small. I have an old kidney shaped pool and Im starting to upgrade all my equipment, based on my signature you can see how old everything is. The pool is plumbed with old school black flex poly, it doesn't even have a stripe on it, so I'm sure its not even meant for a pool. this pool is super old and still has the old metal return flanges. My big concern is at 1.5 inch piping it will only provide 42GPM of flow. I am also thinking of putting in a VS pump, the 266BTU will activate and heat with flow as low as 25GPM, where as the 336 will activate at 35GPM. if Im using a lower speed (once i buy a new pump), but want to heat at the same time, would it not be more beneficial to go with the 266BTU heater?