"retired53" [email protected] writes:

I bought this house with an in-ground swimming pool 2 years ago.

Never had any problems until now.

Just recently it started getting air bubbles coming out of one of the spa
input jets. I can hear some air going through the plumbing near the
filter/multi valve. I don't see any bubbles going into the main pump filter
basket.

Look for leaks on the intake side.
Start at the skimmer.
I've seen little whirlpools develop in the skimmer
letting air into the system
especially if the water level is low.

I've also noticed more sand in the pool from the filter

As others said, a little sand is no big deal.

The laterals are arms at the bottom of the sand filter
that let water exit the sand.
Wait til you want to change the sand before inspecting there.