Sand filter sand level only 1/4 full!

[jfdid]

I went to deep clean my sand filter today as we just bought the house last fall. Astounded to find that the filter was only ~1/4 full of sand. I've read some folks have sand only a little above 1/2 but 1/4 is a bit low! I wonder how it has lost so much sand.
Not knowing the pool well, I suppose it could have been vacuumed to waste at some point. I'll check the laterals when I pull it apart to replace the sand.

Any thoughts on what other steps I should take?

Thanks!

 

[DrZach]

Probably laterals, however,
Mine had this same thing when I first bought the pool and the laterals were all ok and it took me a while to track down the problem the next year but the bottom of the main stay pipe was cracked in from the previous owner somehow over-tightening the valve down with force or not having the bottom of the tank fully clean or the valve head not being fully cleared out or something because the black base was cracked in, essentially blowing sand out every time it was backwashing only (must have been something with pressure gradient) because sand was not being blown into the pool.

 

[jfdid]

DrZach, thanks for that info. I'll take a good look when I pull it apart today!