We have a 15' Intex with inflatable ring. It was brand new last summer with no leaks. I put it away dry and clean last fall (and away from where kids could reach it in the garage). I set it up last night and began filling and with a couple inches of water in it it began leaking from underneath. I inspected it before filling and did not find any holes. Could it be leaking at the seams? Any ideas on how to find the leak would be appreciated. It is a bit unwieldy. Thanks!