I just bought a house with a 25000 gallon vinyl in-ground pool. Just learning this pool stuff. The pool is about 20 years old. I have a 48 sq ft Nautalus NSS-48 DE filter and a aqua-flo "A" model 2 HP pump. No check valves. After replacing the dead pressure gauge I only get about 4 psi at the filter with clean grids and a new load of DE. Flow back to the pool seems strong to me. Is this correct? If not, whats likely wrong. I had to reassemble the filter grid assembly twice. The first time I was getting some DE settling back in the pool. I'll check this afternoon and see if I got that problem fixed. I did replace one grid that had a 2" tear in it. I need to limp through this season with this filter as I'm really cash poor after buying the house.

I have a 28K gallon inground gunite pool that was put in about 4yrs ago. Until about a year ago, I've been adding muriatic acid on a somewhat regular basis to adjust the pH down. I've also been using Trichlor chlorine to slightly reduce the amount of acid I need to dump in. Funny thing is that I haven't had to add any acid since... and I've already started using Dichlor chlorine. pH, alkalinity, and hardness are ok as is cyunaric acid levels. Is this normal? Are you inground pool folks still adding acid every once in a while? I doubt if makes any difference, but my pool is covered at all times and is open only when we swim for about an hour a day.