I just went to his website http://www,ener-chi.com and checked under suppliers but I could not find a recommended brand.
So may be someone else might have suggestions.
I always used prill water but I can't remember the PH of it. I have some stones left and might try it again and check that out. That is really cheap to do. The company for the prill beads is under suppliers on his website, in case you want to read about it.
The link from his forum did not work so you can google it. The Wolfeclinic sells them. I have been using it for years, but since we were away for several months I decided to throw out the water. I use them in the toilet tanks too to keep the water clean.
I will start up another jar, after I buy a new glass jar, and will let you know what the PH is by the end of this week.