I am having a similar issue, and I think the high TA fill water is also the culprit. My fill water is TA 140, which I just measured for the first time today. I can knock my PH down to 7.0 or less with a gallon of 14.5% MA, aerate over the weekend with my aerator water falls, and bring the TA down to 70 and PH to 7.6, but then in a few days or maybe a week I am back above 7.8 and TA 100. It was making me crazy until I checked the fill water today.
Any suggestion what to do about TA if your fill water is high TA? I think the answer will be "stock up on MA". Ugh. I was hoping to add borates, but now I am thinking that will just make it harder to bring down the PH and TA when they inevitably drift up.
Any suggestion what to do about TA if your fill water is high TA? I think the answer will be "stock up on MA". Ugh. I was hoping to add borates, but now I am thinking that will just make it harder to bring down the PH and TA when they inevitably drift up.