Air/sand entering pool thru returns-weak polaris troubleshooting help needed

[Mutzy]

Hello- I am struggling to resolve several issues in my pool. I'm not sure if these all point to one common issue or separate issues. Any guidance is very much appreciated!

Issues-

• Both air & sand entering pool thru return lines
• Polaris 280 weak operation
• Main pump continuously pulls in air

Steps taken to troubleshoot(no particular order listed)
Pool water level good
Pool skimmer wier working
Pool skimmer basket clean
Pool pump lid O-ring appears fine
Pool pump lid appears fine
Pool pump basket clean
Garden hose leak test(& shaving cream & soapy water tests- done seperately) at pump & nearby plumbing didn't seem to detect where air was entering system
Found Hayward S200 filter WAY low of sand(it's all at the bottom of the pool)
No noticeable issues with laterals or downpipe(more review to be done today)
Blead air vent on top of filter
Pressure tested skimmer line between skimmer & inlet to Jandy valve w/no noticeable bleed-off(although did bleed down over night although suspect could have been due to weak expansion seal I used at Jandy?)
Pulled my hair out

Vinyl 25k gallon inground installed in '79.

After no-show from local Pool company I'm looking to see if you could provide suggested troubleshooting steps to diagnose & resolve these issues.

Thank you for your time & input!

 

[wireform]

Mutzy
Hi and welcome. Please fill in the signature portion and pictures of your equipment pad so we can see what you have and limit the back and forth questions. Give us some history and previous troubles and how are you testing and chlorinating.

 

[Mutzy]

Thanks Wireform for the signature suggestion! I have updated.

A little update on the sand filter I found earlier this morning-
I have found that the internal elbow pipe(bottom, SX200C1) had a hairline crack on bottom/inside of bend(item #11). Also noted NO O-ring as shown on parts diagram at bottom of Lateral holder assembly(SX200QA)(item 14). So my suspicions are one or both of these was allowing sand into return lines? I plan to replace both. Thoughts on this?

Any thoughts on original air issue and sluggish polaris?

 

[wireform]

I'm not sure on either of the two questions but can't imagine the filter working without the big gasket.