I'm not exactly sure how many gallons are in my pool. I keep seeing different amounts from different places. My pool is 27' round 48" deep. I've seen some that say 15,054, 15,500, 16,500, 17,200 etc. I found a calculator that says to multiply 27 x 27 x 4 x 5.9 to get my answer. Can anyone help me out so I know how many gallons of water I'm treating. Thanks a ton.