Carolina,
Poolsean's thought of the drain plug on the pump strainer basket makes a lot of sense. It is possible it would be loose enough to allow air to suck in. I doubt you would see any bubbles in the strainer lid because they are immediately pulled into the pump. That said, I'd think the bubbles would show in the basket lid once the pump was turned off....maybe not. Anyway, it's really easy to ensure that it's tight.
Poolsean, like you, I am very interested in tphaggerty's problem. I remember it very well and am completely baffled that that can happen in an IG pool.
Poolsean's thought of the drain plug on the pump strainer basket makes a lot of sense. It is possible it would be loose enough to allow air to suck in. I doubt you would see any bubbles in the strainer lid because they are immediately pulled into the pump. That said, I'd think the bubbles would show in the basket lid once the pump was turned off....maybe not. Anyway, it's really easy to ensure that it's tight.
Poolsean, like you, I am very interested in tphaggerty's problem. I remember it very well and am completely baffled that that can happen in an IG pool.