RoDi unit question

Hey everyone I had to take down my Spectrapure RODI unit for about 2 years the filters and everything were hardly used when I unplugged it, however as I said it sat for close to 2 years. My question is should I just replace everything or what would you suggest??

 

Replace them

 

^^ replace them seconded

 

Hmmm... I can't imagine how they would go bad by just sitting. I'd say at least try it first- hook it up and run it for 10 minutes or so and then test the output. As long as you're getting zero TDS, your filters are fine.

 

Were the filters stored wet or dry???

 

I ran them and unhooked them so they were stored wet. It's not to big of a deal to just buy new ones. I would just like to save some money if possible.

 

Once a RO membrane has been used or wetted it must always stay wet, once it dries out the membrane fabric is ruined.

My recommendation is to first hook the system up, let it run for an hour or so and test your tap water TDS and your RO only TDS before the DI. We can be assured the DI resin is shot since it has a short shelf life even when new so testing the RO/DI TDS won't tell you much.

If the rejection rate (rejection rate is calculated by taking the tap water TDS, subtracting the RO only TDS then dividing that number by the original tap water TDS and multiplying the resulting number by 100) is still in the 98% range your membrane is still good.
An example of calculating the rejection rate would be say your tap water TDS is 250 (the national average) and your RO only TDS is maybe 6. 250-6= 244, 244/250= 0.976, 0.976x100= 97.6% rejection rate or removal efficiency which is still pretty good.

I would replace the sediment filter and carbon block with no larger than their 1.0 micron versions with the 0.5 micron preferred and the DI with either a SilicaBuster or a new Super SilicaBuster cartridge which lasts about 30% longer for only a couple $$ more in initial cost but actually saves you money with the increased lifespan. The sediment and carbon may still be good but they could also be harboring bacteria or viruses too so not worth the risk for a $20-$25 savings. You can get a kit with the sediment, carbon and DI all for one price.

 

You say the shelf life on the resin is short. How short? I had a bag about 7-8 months in the garage and used it when I replaced the other filters and my TDS is reading no better than 3 now. Could that be the reason??

 

Yes.
Resin, even when vacuum packed in a mylar foil bag, unopened and stored in the refrigerator or other cool place away from direct lighting has a shelf life of about 6 months before it starts losings its electrical cation and anion properties. Never buy more than you can use in 6 months time and it is best to buy in individual 20 oz portions or prefilled cartridges or when you receive it divide it up in 20 oz portions and seal them up with a Seal A Meal type vacuum sealer and store it in the back of the refrigerator. Resin stored opened, in bright lighting or in warem temperatures starts degrading immediately. It must stay damp, cool and out of lighting so vacuum sealed and in the frig works well.

 

Well, I just learned something new. Thank you for the info, AZDesertRat.