If you don’t see a hole/tear in the vinyl, the first step is to double check the air valves. If they are not completely shut tight with no gap at all, the pool can slowly deflate over time—especially when filled with water. This can be the case especially for the top ring because once filled with water, the water pressure stretches the bottom two rings of the pool and puts tension on the top ring. If it’s not pinched completely shut, this tension can pull it loose… causing the top ring to lose air. First try adding more air through the one way valve of the top ring using your breath (DO NOT use an electric pump when the pool is filled with water) and then pinch it shut completely.
For photo references of what the valve should look like when properly closed. Please visit our HOW-TO page. Photo references are located at the bottom of the page.
If you’re trying to locate an air leak, you can sponge soapy water around the entire pool—most importantly around the seams. Bubbles will appear where air is escaping. You can also put your ear up to each ring to listen if it sounds like air is escaping when you gently squeeze on the ring.