New 4x40 end caps

[cjf12]

Rebuilt the ro to have 3 membranes. Everything seems fine other than the fittings coming from the caps are leaking. Is there a better alternative to the cheap plastic caps?

[maple flats]

Any I've seen used plastic end caps. You should be able to get leak free connections, I suggest a good quality joint compound paste. Some use teflon tape, but in reality that is not suggested for screwing into plastic. It lubricates too well, and you can actually create a crack in the plastic by over tightening. That being said, many use it.