RO/DI problems- can it be?

[gregr]

I changed all the filters in my ro/di unit about three months ago and the di cartridge was replaced about 5 weeks ago. A few days after I replaced the di cartridge the tds was zero. Just now tested the water with a TDS meter and it was 90ppm! How can that be? This is a good ro/di unit bought new from APS Water. They're local so I buy all my replacement filters from them too. Woe is me

[gregr]

With the help of the guys who made the ro unit I figured out what happened. I had changed out the three filters before the ro membrane but not the membrane itself. The ro membrane was on it's way out when I got the new di cartridge so the bad ro membrane was letting a lot of dissolved solids thru and that killed the di cartridge prematurely. Lesson learned. Got the new filters installed and tds is back to zero.

[charlie]

I saw this earlier and was gonna ask if you had changed the membrane. Good deal you got it figured tho!!!!

[gregr]

Thanks Charlie- wish it hadn't taken me so long to figure it out though.

[charlie]

This hobby is so humbling at times!!!!