Hello all, at the end of June I replaced the old cartridges in my Hayward C5025 with new ones. I opened and closed the unit as I had done many times before to access/clean the cartridges. Upon turning the pump (Hayward super pump 700 series) back on I noticed a small leak at the clamp system where the upper and lower filter bodies meet. The leak stopped when water started coming through the air relief valve but I decided it might be best to go through the process again. No leaks but...

In short I've had issues with the pump not priming since then. I've had my pool service out twice, they've inspected and lubricated o rings, tightened the clamp and installed a new air relief valve. It was priming for the last week or so since their last visit, albeit kind of slow - I was not seeing water coming into the pump strainer basket until about 40 seconds after the pump turned on and water didn't start coming out of the jets until about 1:40. Yes, I timed both. Unfortunately, today it didn't seem to be priming at all so I had to turn the pump off and fill the basket with water, just like I was doing throughout late June/early July.

My pools guys think it is possible that the underground pipes have been breached or damaged by the roots of a large bush that sits between the pool and the equipment so I am prepared to have this removed in the Fall so they can access the pipes. My concern is that everything was fine until I opened the filter up as noted above so it seems to me I caused an air leak somewhere on the equipment side that has yet to be detected. I should note that when the pump turns off at night there is a rush of water from the filter/pump to the pool that basically pushes out the skimmer baskets and covers. 

Thanks in advance