I've been using the TFP method since last year with great results. Thank You.
When I started TFP, my TA was 100 ppm but is now down to 60 ppm, due to aeration/acid addition cycles. I thought as my TA became lower, that I would reach a point where pH would be stable and quit rising (the happy point). But at TA of 60 ppm I still see my pH rising to 8 over a weeks time, and have to add acid about once a week to bring it down. When I do add acid, I usually bring pH down from 8 to 7.2, which lowers TA a bit more. So I expect my TA to continue dropping.
1. As my TA continues to get lower, due to aeration/acid cycles, will I get to a sufficiently low TA, such that pH won't rise any more (even with aeration continuing)?
2. My TA is at 60 now. If it keeps dropping, at what point do I need to start adding baking soda to increase it?
3. Is there an "unhealthy" low point of TA? Or would something lower than 60 ppm be OK as long as I make sure CSI is in the OK zone.
Here is a picture of my aeration. Currently, any time my pump is running the lions heads and spa fountain are operating as in the picture. I only run the pump an hour or two each day.