Hello Pool Experts,
I'm at my whits end with this, so I thought I'd see what I might be missing.
I have a 15-year-old 10,000 gallon in-ground pool, currently getting SLAM'med to get rid of a stubborn green algae bloom. But in the course of this, I have noticed that I'm getting a lot of air coming in to the skimmer basket when the pump is running.
The pool and spa run off of one variable speed motor.
The intake can be adjusted to be either the spa, or the pool (skimmer and floor suction OR vacuum intake on the side of the pool).
The outflow can be set to either spa, or pool (outlet on side of pool, or two waterfall features).
I've put a diagram below that approximates the plumbing layout (the main difference is that the "Pool Intake" can be switched to either the skimmer or the vacuum intake on the sidewall).
The water level in the pool is good, and there's plenty of water for the skimmer basket.
For some reason, when the intake is set to the "Pool", the strainer reservoir won't fill up with water when the pump is running. It pulls in water, but also a lot of air.
I've done some experimentation, and when I put a hose in the strainer with the intake set to the pool, it will never fill up above the intake pipe in the strainer. The water just flows out, back towards the pool. I have no idea where it is going, because the pool doesn't appear to be getting any water (and the pool outlets are below the level of the pool equipment, so that would make no sense). If I set it to "Spa", the strainer will fill up to the top. But if I put the lid back on and start the motor and then switch back to the pool, it starts drawing in a lot of air.
Does anyone have any idea where the water from the hose is going, or where the pump is drawing air from when it is turned on?