You had tap water TA of 60 (I looked up your older posts -- my memory is not that good) so it would be hard to get below that if you are refilling your water periodically. On the other hand, your rains probably have low TA. At any rate, Ben's Lowering Your Alkalinity procedure is the only sure-fire way to get your TA lowered. By the way, when you quote TA, please don't adjust for CYA. Instead report TA (as measured by the test kit) and CYA separately. That avoids confusion.

As for where to add the Borax and how much to add how quickly, that's a question for Evan (waterbear) or others who have used Borax to answer as I have no experience with it so don't know how quickly it dissolves.

Richard