Memtech R.O. Problems

[Quabbin Hill Farms]

I have an older Memtech R.O. mr 40 I think it has 3, 19" membranes, bought it last year didn't seem to work well so I replaced the membranes.Started it up today good flows here finally, the manual and the instructions on the cabinet say to adjust concentrate flow to .5 gpm and then using the permeate flow valve adjust to bring the pressure up to 500 psi. The only way I can get the pressure that high to to totally close that flow valve but then the permeate flow is 2.2 gpm. When I first started up the pressure was close to 500 and I was getting 5.4 % concentrate, then I seemed to lose pressure it dropped to about 400 psi. I also have 2 % in my permeate flow as well.

Anyone with one opf these older models have anything similar happen to them.

Any information wouldbe appreciated.

Thanks