Hello,

Three years ago I built a small scale RO for my 70 tap operation using plans that came from this site. It has worked flawlessly! I started with three 150 psi membranes and added a fourth this year just to help speed it up a bit....also worked well. From year one to year two I rotated the membranes so #1 membrane went into the last place and the the #3 went into the first spot, etc. I have been very good about flushing the membranes every so often during the season using hydrogen peroxide solution as described in the build instructions...again from the instructions. I did the same procedure at the beginning of each year and also at the end of each year. Then I store the membranes in the refrigerator first wrapping the wet membranes in plastic wrap and then vacuum sealing them to keep them air tight for the year. I run my little ro at 130 psi and have a pressure gauge before the #1 membrane and another gauge after the #4 membrane. I have never had any issues with pressure dropping from the first gauge to the second gauge.

So, all that said, when I looked at my membranes after this season I see that membrane #1 (three seasons under its belt) I notice that it looks pretty brown on both ends as you look at it from top and then bottom. Less discoloration on membranes #2 and #3 (also 3 seasons), and very little discoloration on the newest membrane #4 (one season of use).

Should I be doing another type of year end cleaning to try to get my membranes cleaner? If so, what is that exact process and what materials do I need? And lastly, how many years of use can I expect from my membranes?

Thanks much for any help!

Jeff
Blue Hills Sugar Bush
Bruce, WI