Pump cavitation

[MKPBrewski]

Hi,
I know very little about my pool, I'm new at this. We had a guy come out and open it a few days ago.
Last year it ran great.
In the site glass of the lid on the VS pump which is a Pentair 1HP programmable, there was just clear water through there, no cavitation last year.
This year upon opening, the pump has a swirl of water that looks like its cavitation.
There was at first what I thought was grey debris or fine grey sand or particulate coming out of the two inlet jets into the pool. The water was cloudy on that side of the pool. But then would clear up. Then go cloudy again.
Now I'm beginning to believe that is not particulate but tiny very dense bubbles.
But then again, I'm not sure.
Not getting much help from the guy that opened it, a few answered texts but that's it.

I'm beginning to suspect there is air getting into the plumbing system. I have no idea how to check for that and isolate where that air leak might be. Like in a pressure line of a gas system, I can put soap bubbles and test for leaks that way. Is there something that works for pool systems? I realize the leak is air going INTO the pipe.

I have a Pentair VS pump. A sand filter, a heat pump (which right now I'm not using until I can troubleshoot the current problem) the pool is about 18,000 gallons and has 1 skimmer and 2 inlet jets.

Can someone give me some pointers?
Is the cavitation that I'm getting this year most likely due to air in the system?
Also is there some tool or indicator that I can use to find which pipe joint or lid is allowing air in? (I suspect the pump lid is because its very hard to get it on and I thought I saw a few air bubbles going in there but not that sure)

As soon as I figure out how to get pics from my phone to my PC I can post pics of the symptoms.

Thanks for any help!!

Mike