How to lower PH during RO wash

[Randle]

Our H2O 600 gph (single 8" membrane) states the membrane should be washed with a PH at 11.0 - 11.5. If we're over 12 what is the best way to lower the PH of the permeate in the wash tank?

[inthewoods]

drain a little water out of wash tank than take a pail of perm. and dump a little back in wash tank to get ph down. what soap are u using? i have same ro and use bio membrane soap and it takes about 20-22oz to get a ph around 11.

[Amber Gold]

I understand the wash soaps we use have a buffer in them so the pH can only get to 12. H2O has a RO presentation on their website that claims their membranes are to be cleaned at pH of 12...claims it's 9x more effective than 11. I still have Lapierre powdered wash soap and have been using it. A 2 oz. sample cup works for a full wash tank...pH starts around 11.5 but finishes are 11.

[Randle]

The H20 documentation is conflicting from the paper manual to the online version. Paper documentation that came with the RO states to wash between 11.0 - 11.5 pH while the online documentation states to wash at 12 as it is more effective. Our pH reading was 12.5 and the membrane worked awesome after the wash so I guess I'll not worry about it too much if we're washing in the 12 pH range.