Air in system + a brief leak at the filter housing

[Lambchop]

My system runs 365 days a year, between 8-10 hours per day. The Pentair pump is 2 1/2 years old but the Pentair cartridge filter tank is roughly 19 years old. I clean the cartridges every three months due to dust, mainly.
Lately, when the pump starts, the system is full of air and slower than usual to prime. I end up releasing the air via the pressure gauge fitting on the tank.
Last Fall while getting ready to remove the cartridges to clean, on start up, a squirt of pool water came out of the pool tank, right where the clamp ends meet. Once before, I had noticed water on the pad near the tank and checked all fittings which were new and none were leaking. That squirt finally showed me where the water came from. So after the cartridge cleaning, I made sure to clean the o-ring (at that time 2 1/2 years old) but wiping it with a rag caused the o ring to separate. This was a knock off brand. So I got an OE Pentair replacement, lubed it with silicone and the squirting it is still occurring. The clamp is on tight, less than 1/4 inch gap.
Wondering if there might be a hairline crack in the tank top or bottom? Anyone experienced this? Is there a way to check other than a magnifying glass?

My main concern, though, is the sudden air in the system that occurs at night between shutoff and startup. What could cause this? This is a 14,000 gal in ground gunite pool with an infinity spa. The spa does not drain down at night.
Jandy valves and o-rings were changed probably three years ago. Is there a way to test the tops of the valves/housings to see if one might be sucking air? Run water on them? When observing the pool water returns on start up, they look like jacuzzi jets...full of bubbles.

Any assistance is appreciated and thanks.
Lambchop

 

[HermanTX]

Please consider adding the description of your setup to your Signature, which will aid the experts to quickly tailor responses to your pool and equipment, and you won't need to repeat it in future posts.
So we can assume you have a Pentair Filter. It most likely has a clamp around it with that big screw that compresses the spring.
If so, that screw/nut on the clamp needs to be tighten until the spring is fully compressed, the coils are touching to each other.
This is most likely causing the water to leak and also could be the cause for air to enter the system when the system is shut off.
Post back a picture of your filter to ensure we are discussing the correct filter.

 

[Lambchop]

Thank you.
My initial thought of using water pinpointed my leak. I used a small plastic indoor watering can and slowly poured water over each joint and each jandy valve and upon pouring water over one specific jandy valve, the bubbles stopped briefly and each time I repeated pouring water on that valve, again the bubbles stopped, confirming my air leak.
In trying to snug down the screws, I discovered two screws are stripped, so now on to repairing that as this is a three way valve installed in a manner that would be a nightmare to replace.
Many thanks for the reply!

 

[Lambchop]

One more hint. I successfully fixed the stripped Jandy Valve body holes using 1/2 inch black irrigation poly pipe.
I cut a strip of poly pipe about 3/16 wide and the length of the Jandy screw, dropped the strip into the hole and replaced the screw. Works quite well, no more air leaks for me. I was concerned about some methods I saw that might fracture the valve body, so using the very flexible and soft poly pipe was my choice. It is soft enough to accept the screw threads and not so stiff as to crack the mounting hole. Depending on how loose your screw is, you may have to practice with different widths of poly pipe. Hope this helps someone.
Good luck.

 

[Texas Splash]

Great you got it fixed. Maybe try to post a pic or two when you get a chance?