If you are having rising pH problems with your salt system a few things can help (since the main cause of pH rise in a salt pool is from outgassing of carbon dioxide):
1) make sure your CYA (stabilizer) is at the recommended maximum, usually 80 or 100 ppm. This will directly translate into less cell on time which translates into less aeration of the water from hydrogen gas generation in the cell which translates into less outgassing of CO2 which translates into slower pH rise.
2) lower your TA to around 70 ppm. TA is actually a measure of the bicarbonate (carbonation) in the water. We keep pools overcarbonated on purpose BUT the higher the TA (bicarbonates) the more CO2 that forms and the faster it outgasses. The faster it outgasses the faster the pH rises. High TA wants to push the pH to around 8.0 all the time.
3)When you lower the pool pH try not to drop it below 7.6 and when it gets higher than 7.8 drop it back down to 7.6 (this is actually easier than it sounds with a bit of practice and getting to know your pool AND having a good test kit like the Taylor K-2006). The lower we put the pH the faster it rises because the lower we put the pH we create more CO2 in the water from the bicarbonate in the water (if you are wondiering what I am talking about pour some vinegar on some baking soda).
4) adding borates to 50 ppm helps stabilize the pH around 7.6-7.7 for an extended period of time. There are commercial borate products on the market or you can use Borax (found in the laundry aisle) and muriatic acid to bring the borates up to 50 ppm.