I live in a location where I won't close my pool this winter. I try to maintain my pH in the 7.6 - 7.8 range as recommended by TFP. However, with a 390 CH and a TA of 50 - 60, I'm finding it difficult to maintain a CSI above -0.3 with a pH of around 7.7 if water temps are below 65F. The only thing I can see to do in the app is a) increase TA to around 70 or 80 OR b) increase my CH. What am I missing?