I made the conversion from baquacil to chlorine, changed sand in my filter. Before I made the conversion I was having to backwash every couple days because I would lose flow from the jets and suction in skimmer, and filter pressure would go up to 26 psi from 23. When this would happen I also would notice that there would be air in the pump basket. after a couple days, basket would only be about half full with water. I would backwash and everything would be fine for about 2 days. I used some acid filter cleaner and that helped some.
Then I decided to go to chlorine, that process is finished and with the sand being as disgusting as it was I thought new sand would alleviate this problem. After changing the sand, I am still experiencing the same problem. After a day the suction and jets flow is very low and I have to backwash to get it back. After backwash the psi is 20, then went up to 25 in a day, flow is low and air in pump basket. Can't find any leaks, and everything alway comes back to normal after a backwash. I'm new to pools, first year. I am perplexed with this and would appreciate any input. Thank you.
25,000 gallon rectangle inground pool
2 return jets, I robot jet, 1 return.
Hayward S200 sand filter