Locating Suction Side Air Leak

[butterblum]

Cavitation in a residential pool pump is fairly rare. In most cases, a seal/o-ring/gasket will leak allowing air into the system well before the pump cavitates so the pump ends up losing prime before it can start to cavitate.

Are you sure the pump was actually cavitating?

100% - the sound is a dead giveaway; I wouldn't exactly call it a popcorn sound, but a mix between popping/crackling and grinding - it only happens at high RPMs when using the vacuum hose.
All of the piping for this pool is 1.5" (built in 1976), and the pump is at the opposite end of the pool from the skimmer. I reality, the variable speed pump is probably slightly oversized for the system - however, it only gives an issue when vacuuming at >3000RPM.

 

[butterblum]

Have you done a bucket test yet, to determine if your pool is actually losing water? Some leaks only occur while the pump is running. A suction-side leak in that case would not lose water. A more severe suction-side leak might not lose water while the pump is running, but would when the pump is off. A bucket test would be another data point in your troubleshooting.

Dirk, I'm not familiar with the bucket test.

 

[Rancho Cost-a-Lotta]

Instructions for the bucket test are included in this link:

Leak Detection

A number of things can cause leaks in your pool. You can learn tricks for leak detection and how to pinpoint where your pool is losing water.

www.troublefreepool.com

 

[wireform]

Dirk, I'm not familiar with the bucket test.

Bucket test