I recently got a leak in my Sea to Summit mattress, which I love. It's a very, very slow leak. A few days before before my tour this past weekend I put a good amount of water in my bathtub and tried to find it. Couldn't. Not one air bubble. I think it only loses air when subjected to the weight of my body. I had to put a few breaths in it one night this weekend after several hour of sleeping on it. REI is having another 20% off sale right now. I think I am just going to suck it up and buy a new one.