It's so bizarre. I pulled back the liner today and filled the bath. It hasn't lost any water all day, even with it being pretty warm today. So, whether the liner has been compromised or not, it doesn't matter because the bath's integrity is sound. So where did the water of overnight? The pump wasn't running, so it couldn't have pumped it out somewhere. I put clamping and wiring onto tubing joints today just to make sure of any leaks there. The only thing left I can think of is that I had a piece of carpet draped at the end of the bath into the water to allow little critters to crawl out if they fell in, which possibly could've been sucking the water out, but there was no pooling of water at the end of the carpet outside the bath, unless it was just evaporating from the carpet itself, which would've been a heck of a lot of evaporation. I'm totally perplexed. Anyway, the bath is full. I have an electric pump running now to see what will happen overnight. I swear this thing is more complicated to solve than the Apollo 11 dilemma.