In testing the effectiveness of the sand filter, I poured a small amount of stabilizer into the skimmer and a portion (but but not all) of it came back into the pool from the wall return. I haven’t seen any sand in the pool so doubt that a lateral is broken; however, all other attempted troubleshooting did not prevent similar results. I disassembled the backwash valve to ensure the O-rings were good – no problems there. I also did a deep clean on the sand to rule out any channeling.
What next? Should I remove all the sand to visually inspect the internal components or is some loss expected?
Thanks for your help.