I don't think you're going to have to worry about damage because your Borates are too high--it takes LOTS of Borax to get to that point anyway! As long as your pH is okay, your TA is ok, then just order some Borate test strips to find out what your borate level is. If it needs to come down, it will do so as a result of water loss--splashout, filter cleanings, etc. If it needs to come up, then you already know how--you are shooting for 30-50 ppm.

I think we were all just a bit confused by your original post, because Borax is generally used to raise the pH, NOT the TA. Sometimes new posters confuse the two, and we were trying to make sure you hadn't. The use of borates through Borax addition has been shown to stabilize pH and act as a secondary barrier to algae, so as long as you understand why you're using it, which you obviously do, then it's all good!

Janet