I have a 28,000 gallon vinyl pool.
I was initially planning on lowering the ph and raising it agian with borax to act as a ph buffer (as I read all the ph problems with a SWG), but turned out I never even had to do that. So i've never used any borax at all in the pool.

My Ph was also stuck at 7.4 all last season, was a little low when I opened it this season but my alk was also low, when I added baking soda to bring the alk up the ph returned right to 7.4 and has been there since.