View Full Version : R/O TDS not 2% of incoming water of 179 ppm - Help

01/02/2008, 04:39 PM
My TDS is 35uS (approx 17 ppm) after R/O replacement. My buddy replaced his at the same time and he is getting 25 ppm with incoming water of 240 ppm. What could be the issue here? We should be getting between 7 and 3 ppm if the r/o is 98% rejection. Any suggestion?

Randy Holmes-Farley
01/02/2008, 05:14 PM
Rejection often is not 98%. I get about 95%, and I have a high quality system from Spectrapure. Yours seems lower than that (90%), and may reflect a less than ideal membrane, or inaccurate measurement.

01/02/2008, 05:18 PM
Check the container you are measuring in, make sure it is a squeaky clean clear drinking watre glass with no soap residue or water spots.
What membrane do you have and how much water have you run through it?

old salty
01/03/2008, 12:06 AM
Water pressure plays a big role in this.

01/03/2008, 08:45 AM
Yes, higher water pressures make membranes work more efficiently.