Need help with R/O build

[gmack]

i need some recomendations for a 5 membrane 4x40 r/o . pump sizes and plumbing to use .

Thank you

[DapperTapper]

4 x 40GPD?
or...
4 x 40"?

[Bricklayer]

5x 4x40 membranes? Your better off going with 1x8” membrane. A procon 660 will work for an 8” membrane. You could then use a multistage booster pump for recirc pump if need be to make it more efficient. But the 660 will work on its own.