I've done some research on borates, and I've decided that I will want to add them at some point. My reasons for adding borates are to:
1. Help buffer against pH rise as the new plaster cures
2. Improve water feel
3. Reduce chlorine demand
4. Make the pool an unfriendlier environment for bugs (every time I mow the lawn, carpenter/winged ants like to come into my pool)
Please correct me if my reasons are misguided. Also, here are my latest full set of test results (excluding chlorine):
My TA has gone down over time, to as low as <60 and had to bring it back up to 80 because of adding MA to hold down the pH. It's been hovering between 60 and 80 for the past month with MA + baking soda.
I have a 12.5k gallon pool and I maintain FC using bleach, so to bring my borates to 40, I will need almost 8 boxes of 76 oz 20 mule team borax ($3.99 per box at Target), plus 2 gallons and a quart of MA to counteract the borax's effect on pH.
So, to tally up the costs, I need to buy 7 more boxes of borax, plus 2 more gallons of MA for $13 at pool store. That will be a total of $45 including taxes. That doesn't include the test strips that I'll need to get as well. Maybe I could skip the test strips for now and just trust the pool calculator, and buy the strips several months later or when I need to test borates?
The ONLY problem with my plan? I'm going to my PB about a plaster mottling problem, and it's remotely possible that I may push them to tear off the plaster and re-plaster properly... this may require a full drain. Should I hold off on the borates until I get more certainty about what the PB is going to do about the plaster job first?