Hard to catch: Leaks in the fiberglass shell are often difficult to detect visually, which is why many companies rely on special equipment — such as ultrasonic detectors or gas sniffers — to pinpoint the problem.
Bad valve: This check valve was leaking, causing the pump to cavitate. It was easy to isolate this damaged part, but not all leaky valves look so suspicious.
Poor suction: This pump was cavitating due to a lack of suction, which was caused by a leaking check valve. Many leaks can be detected and repaired outside of the pool.
Simple fix: Once you’ve determined the rate of water loss, start by checking the plumbing, especially on the suction side, to try to isolate a leak; if you find it, just swap out the bad pipe or valve.
Add some color: Using a syringe without a needle, inject a small amount of dye or food coloring into the water, about an inch from the spot where you suspect the leak may be.
Cracking up: Shells sometimes develop cracks that are visually obvious; these are often already too large to fix with a quick epoxy injection.