I ordered my boric acid from Duda Diesel. It was recommended elsewhere to make sure to order the granular version, as opposed to the powdered version.
For 25 lbs, the price was just slightly more than the equivalent amount of 20 Team Mule Borax, and way cheaper if I added the amount of muriatic acid I would have needed to use the borax route instead of boric acid.
Also the process was very easy. I broadcast the boric acid across the pool, then swept with my brush, walking around the pool two times. By the second time around, the boric acid had completely dissolved. I checked with my test strip, and it looked to be right at 50 PPM.
In my case, pH dropped from 7.5 to 7.3 after adding the boric acid.
Why is granulated recommended over powdered? My initial thought would be that powder will dissolve and mix in with the water much faster.
Also, I have about 21000 gallon pool. The pool calculator calls for 40 1bs. by weight of borix acid. Sounds like a lot to me. Does that sound about right?