no, the filter pressure isn't rising. I went back to the pool store yesterday for new readings: alk was still low at 46, so I added 11 pounds of baking soda last night. I also shocked it again. I had read about the calcium being irrelevant with vinyl pools and mentioned that to the pool store owner. He said there is calcium in the liner that the water will try to leach out if the water isn't kept high enough. Don't know if he's misinformed or what. He's a pretty honest guy and doesn't try to pressure you to buy his stuff. Does the testing for free if you buy from him or will charge you a small fee just to test. The reading this time showed cya0f 100! Could it really go up that much in 6 days? Pool guy thinks cloudy mess is dead algae....