My pool was completed in November '07. since then, I have lots of trouble keeping my Ph down. I use the pool calculator and the test kit from here. I know that newer plastered pools have high Ph, but for how long? Mine is about 7 months old now. My alkaline used to stay between 100-120, but now that is staying around 130. I keep adding dry acid according to the pool calculator. How long can I expect this to go on?