RO DI problem

[MGBRoadster]

I normally change my DI resin about once a month (say 600 litres of product water) and my 75 GPD membranes last a year or more.

I got a new membrane and new batch of resin and fitted them at the beginning of September they lasted nearly 3 months before the TDS got up to 3ppm.

My most recent change was on 14th Dec when the TDS had got up to 5ppm. Five days later it's already up to 5ppm. It's at 7ppm after the RO membrane.

It looks to me like the membrane is failing. Any suggestions what's going on here? What am I doing wrong?

Chris

 

[soggybongo]

Should be your pre filters you change more often. Di resin should last a lot longer than that.
Ensure you flush the system before and after, also fit a tap on waste and clean water exit pipes to keep system under pressure and full of water.
Also fitting a booster pump will help.

 

[MGBRoadster]

Should be your pre filters you change more often. Di resin should last a lot longer than that.

Yeah that's what I thought.

I put in a new sediment filter three weeks ago, and a carbon at the beginning of September - I thought they should last much longer than that.

I did a couple of other checks today. My tapwater is 330 TDS, but it's only down to 318 by the time it gets to the RO membrane, so it looks like the Carbon filter must have failed.

Thanks for suggesting putting valves on the waste and product pipes. I hadn't thought of that.

Chris