Quote Originally Posted by carls47807 View Post
A 330 gph is probably too much flow for a single post unless you have a recirculation line. The membrane is only going to pull 50 gallons of water per hour, so you would need around 280gph of concentrate flow to keep from hitting the pressure regulator bypass.

You would want at least a 1hp motor for the 330gph (probably more like a 1.25 or 1.5hp). Using a 3/4 hp will only get you around 150psi (and probably still not a full duty cycle).


330/60 = 5.5 gpm.

Most 4x40" membranes will handle 14-16 gpm depending on the manufacturer & model. A lot of people run Procon 330's on 3/4HP. Might not hit the optimal pump curve, but it works.

Passive recirculation increases flow across the membranes which keeps them cleaner longer. Passive meaning teeing off some of the concentrate after it comes through the membrane, then feeding it back into the output of the pressure pump before the membrane. Use another needle valve to lower the pressure of the recirculation line.

I ran my 330 on a 1 1/2 HP but used 2 posts in series. Still 5.5gpm, actually a little more with a LP feed pump.