Last June I purchased your 60,000 gal PL7704. It worked great up until a few days ago. During the winter months here in San Antonio we kept the Chlorine between 3ppm and 5ppm. Last season we used the super chlorinater several time without any problems. A few days ago, following a lot of rain, the chlorine dropped to 3ppm and I attempted to super chlorinate it. I ran it all day and the chlorine never got over 3. I thought maybe the cell was dirty and took it apart and soaked it white vinegar over night. I put put it back together and ran the super chlorinator all day again and once again it never got over 3. Yesterday I took it apart again and this time cleaned it with 5 parts water and 1 part muriatic acid. It's squeaky clean. No calcium at all. I put it back together and ran it all day again and it still doesn't get above 3. I used both test strips and chemical testing and got the same results. The salinity is 2.9 according to the local pool store test. However my control box said it's 3.8.
Would appreciate some suggestions. Thanks