Rapid Mixed Bed Resin depletion

[stolat01]

Hi, my RO/DI water output indicates zero TDS, which is great, but I have noticed that my dual mixed bed color-indicating resin canisters in my RO/DI system deplete very quickly, maybe yielding 50 gallons of water for one 10" canister. This makes no sense to me because I also have individual cation and anion color-indicating resins upstream and those show virtually no depletion. I expected either my cation or anion resin canisters to deplete faster than the mixed beds. Instead, most of my resin depletion occurs in the mixed beds, which are anion color-indicating. Why would that be? Is this all silica that only the mixed beds can address? Is there something wrong here or a different configuration I might want to consider? I start with City of Houston water, if that helps anyone with understanding my starting water source. thx.

 

[Crabs McJones]

Welcome to R2R!

#WelcometoR2R

Do you know what the TDS going into your DI cartridges is? When was the last time your pre-filters were changed out?
If it's city water I wouldn't think CO2 would be a problem, but may be something to look into as well

 

[stolat01]

Input TDS is currently 181, and that is a typical figure. Pre-filters were changed out around 200 gallons ago. Membrane pressure is below 40, but not much higher than that when pre-filters are new.

 

[Crabs McJones]

Input TDS is currently 181, and that is a typical figure. Pre-filters were changed out around 200 gallons ago. Membrane pressure is below 40, but not much higher than that when pre-filters are new.

Input tds to your DI is 181?? That will deplete DI very quickly. You might need to up the pressure to your Ro membrane for a higher rejection rate.

 

[chipmunkofdoom2]

Could you clarify your DI setup? You mention that you have dual mixed-bed resins, then you mention that you have single bed cation and anion resins up-stream? Does that mean after your dual mixed beds?

Also, can you clarify your TDS? It's helpful to know the TDS out of your tap and the TDS after the RO membrane, but BEFORE the DI resin.

 

[ccoffel81]

I believe there isn’t enough pressure to seal gasket around the ro membrane causing the water to pass through. Just my thought.

 

[mr9iron]

Do you make large batches or small batches of RODI water? I had this problem when I left my incoming water on all the time. I would pull a few gallons from the bin and the RODI unit would immediately kick on to replace what I took. My DI resign exhausted very quickly. So, I started making only large batches and my DI lasts at least twice as long now.