Ro/di ?

[drillsar]

I think I need to change both my membrane and RO Filters

Tap TDS 363

Membrane 51

RO 24

DI 4

Its a dow membrane 75gpd I beleive it should take 98% and its only taking 86% so that means membrane bad correct?

Now on my RO filters the sendiment I can see some brownish stuff

Thanks

[dwd5813]

i'm a little confused about what the readings you post represent. i get the tap and di readings, but what's the difference between membrane and ro?

[drillsar]

TDS Source 363,

I took the line straight to membrane, thats where it shows 51

Membrane should take 98% I beleive so it should read 8 on RO instead of 24, so I think I need new mebrane and filters

[dwd5813]

how are you figuring the rejection rate?

[dwd5813]

without knowing your numbers when everything was brand new i can't say if your membrane needs replacing or not but what i get is a rejection rate after membrane of around 93%, assuming i'm calculating properly. if it did start at 98, yes replace it. if not it's probably just time for new pre filters and resin. if you're not sure, replacing the membrane might be a good idea just to be safe but as far as i know they last for at least a year if not longer.