few days ago--sand blowing back into pool
replaced 1 lateral, all things good
two nights ago, sand blowing back into pool from shallow end return only, after pool was running fine for a feww hours--turned filter off
yesterday, turned filter on and all returns ok--no sand
started to vacuum sand on low end steps--no problem--thought , ok , great, finally filter is working correctly
vacuumed sand by low end return and just as i was almost finished by the low end return, sand started blowing into pool thru low end return
turned filter off ( after a few choice words) and had a beer.
so, whats next? take apart the filter to check to see if any laterals are cracked?