Quote Originally Posted by Charrua2 View Post
Richard,

A quick question since I struggled this year with PH continuously sliding up after having incorrectly assumed that I could avoid this by raising the TA to 120 (prior to reading your comments that lower TA could reduce this upward movement in PH). I can only find where you clearly state that it is not a problem to lower your TA to even 50-60 for a liner pool. I have a gunite/plaster pool and was wondering whether it is also safe to have TA at those low levels. Thanks.

Alex
Alex,

If you lower your TA, then you make the water more corrosive in terms of gunite/plaster/grout so you would need to compensate by increasing Calcium Hardness (CH) or keeping the pH higher or both. However, you generally don't run into problems with corrosion (or scaling, in the other direction) until the saturation index is quite a bit out of whack. Nevertheless, if you post a full set of numbers, especially for your pH, CH, CYA, salt level or TDS, current TA, and temperature, then I can give you an idea of where you are currently at and what you can do after lowering the TA.

Richard