RO/DI O ring lube

[mike31154]

Just thinking out loud here, but contamination shouldn't really be an issue regardless of what you use (within reason). Does the O-ring end of the membrane not seal the area around the discharge line? If so, the worst that can happen is your waste water may get contaminated with whatever lube you use. Having said that, if the O-ring is relatively new & supple, there should be no need for any lube at all. If there was, one would think paperwork with the new membrane would include some guidance in that regard?