Can I use my RO unit?

[zoohed]

Ok I have had this RO unit for about 5 years. I haven't made water with it in about 2 years but when it was used it only made maybe 100 gallons. Think I can use it as is? Change the filters and DI resin and use it? Or just scrap it all together?

[burtbollinger]

can you backflush?

[zoohed]

I think I added that from BRS last time I changed filters. Not sure how to use it but it is there I think.

[Water Dog]

My guess is the membrane and DI is probably dried out. If it is you'll probably need a new RO membrane and DI resin. The prefilters may still be good as they've only had 100 gallons run through them. I don't think letting those dry out does any damage.

 

If you have a TDS meter, try setting it up and see if it produces water. If it does, check the TDS. I tried to use my old unit that I had that was sitting idle for 3 years and when I hooked it up, little to no water was getting through the RO membrane. I ended up replacing the membrane and all the filters.

[zoohed]

It has been sitting "wet" if that makes any difference. Running and seeing what my TDS was was my initial thought but I wasn't sure if there was anything else to worry about.

[AZDesertRat]

Make 10-20 gallons of RO only water to the drain and see what the rejection rate is. Measure your tap water TDS and your RO only TDS to calculate the rejection rate. Tap TDS - RO TDS, divide that number by the original Tap TDS then multiply that result by 100.

Example tap TDS 200, RO only TDS 4, 200-4=196, 196/200=0.98, 0.98x100=98% rejection rate or removal efficiency which is where you want to be.

 

Another big concern is bacteria growing in the housings, take it completely apart and wash it well with mild soapy water and rinse well. Then reassemble the housings without any membrane or filters in them and run a couple spoonfulls of regular unscented bleach through them and let it sit a couple minutes with the solution in it before rinsing and installing the new filters.

[zoohed]

6 minutes ago, AZDesertRat said:

Make 10-20 gallons of RO only water to the drain and see what the rejection rate is. Measure your tap water TDS and your RO only TDS to calculate the rejection rate. Tap TDS - RO TDS, divide that number by the original Tap TDS then multiply that result by 100.

Example tap TDS 200, RO only TDS 4, 200-4=196, 196/200=0.98, 0.98x100=98% rejection rate or removal efficiency which is where you want to be.

 

Another big concern is bacteria growing in the housings, take it completely apart and wash it well with mild soapy water and rinse well. Then reassemble the housings without any membrane or filters in them and run a couple spoonfulls of regular unscented bleach through them and let it sit a couple minutes with the solution in it before rinsing and installing the new filters.

I ended up replacing RO membrane and all media. The DI resin started to change as I was making some water to test and said forget it I may as well just upgrade. It was a 35gpd so the upgrade was worth it. I did clean out all canisters but did not flush with bleach hopefully all goes well. Thanks for the input. I knew there was a water guru that hadn't showed up yet.