RO membranes

[StirCrazy]

Originally Posted by reefermadness

Apparently I did. I didnt realize that the 100gpd and 150gpd membranes that BRS sells are not dow filmtec. I got that spec sheet from their website.

How ever my understanding still is that all membranes must be used at the spec pressure to achieve the best rejection rate. You can up the pressure but you will see a decrease in the rejection rating.

You are right that all dow membranes are spec at 50psi. The 100gpd has a poorer rejection rating though, and they don't make a 150gpd.

there may be a slight decrease in rejection rating, but it is not one that would be measurable and definatly not enough to be worried about.

we routeenly installed systems which were intended to make drinking water from untreated water and we would set them up at 100PSI. send in water samples and they would come back just as good as the plaves that have lower pressure. We also checked with DOW engineers befor setting them up this way. what we were led to believe is even at the max operating PSI of 150, the DOW filmtec would still have a better rejection rate than other brands. now this was about 8 years ago so who knows the quality of the copy brands now.

Now from running my own RO, at 50 PSI I get 0 PPM out, at 125 PSI, I get 0 ppm out. now that was with between 20 to 60 PPM in (depends on time of season)

Steve