Phil;

You have two issues, and you need to keep them separate.

1. For whatever reason, your pool's pH has run high, and for whatever reason, you have not responded full to this. Sustained high pH **will** damage your pool. You need to do what it takes, WHATEVER that is, to manage your ph. You need to get muriatic acid, learn to handle it and so on. But first, you need to make SURE you have a good test kit -- either a HTH 6-way, stocked at some Walmarts or a Taylor K-2006 (link in my sig) will do for now. But get one, and check your pool. Then, do what you need to do, whatever it is.

2. Your SECOND issue, is to discover why your pH continues to rise. It could be chemicals you use, it could be the source water, it could be a fountain you have. But, this issue is SECOND. You need to fix the FIRST one, first.

Best wishes.