I've been working on lowering the TA of my pool as my ph climbs far too often due to built-in aeration. We have an integrated waterfall from the spa tub overflow spilling into the pool that cannot be shut off, or the spa receives no sanitation. I have tried balancing the spa drain with the fountain fill in the spa and found that to be an exercise in futility, so the excess spoils over into the pool.
Anyway, yesterday I dropped the ph to 7.0 and TA was around 80. Today, ph reads 7.2 and the TA reads at 60. My goal was to get TA to 50. My understanding is that the addition of MA is what actually lowers TA, so even though the ph reads 7.2, I need to add more acid to get that last 10 points, correct? Should I drop it back to 7.0 with a little more MA, or is the TA still dropping because the water is slightly more acidic than 7.5?