I have found that all my ph problems went away when I purchased my RO-DI unit...
Also, by using Advanced Nutrients 3-part I get a 5.8 reading after adding G-M-B,
because there Advancede nutes ( they are formulated to be used to grow Medical Marijuana exclusively) are ph balanced to use in distilled/RO water...I then proceed with additives. No problem since using RO water...Is such a joy to add 3-part, get out ph pen, and watch it zero in to 5,8...goodluck