Airablo Caustic Soap with a Mark E8?

[Sunday Rock Maple]

I've got a 25 gallon wash tank on an old Coster B300 RO (with no heater) that I've been heating water to 83 degrees F. and then adding the Airablo caustic (white powder) soap into to try and target a ph of 11. It seems that the ph jumps to 13 (using strips) with just a 1/8 cup of soap and the membrane is not coming back to the factory level (8% sugar at 1.5 gph with a permeate flow of 4.3 gph. Should I be adding more soap or a higher temperature?

[Mark]

Add too much and the membrane will be done, if it does not pass sugar you are lucky. Get a good Hanna ph meter. Mix the caustic in a jar of water and very carefully ad a little bit of that to the wash tank. Do repeated washes but don't go over the limit.

[sapman]

I've been able to use very little soap when washing, as well. But my machine auto shuts down at 115. And I've heard the soap doesn't really "activate" til 110 or so. So wash longer for a higher temp, and check Ph again.