Our 18 x 36 inground vinyl pool seems to be losing water for the first time this year. I would say about 1/8-1/4 inch per day. Could be evaporation, as the St. Louis area has had a lot of rain all summer and it hasn't rained lately (where I live). What are any other pool owners in the St. Louis Metro region experiencing? Is this an expected amount? I'm getting ready to do the bucket test tonight but I am so worried!