High Tide Aquatics

RODI problems

M

Meshmez

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Anyone have any ideas what could be going on with my RODI system?

I have a 7 stage with separate cation/anion/mixed DI. All of a sudden I have 10 TDS going into the cation, and 11 tds coming out of the anion.

Anion was fairly newly refilled, so I took the canister off and tapped it on the table a few times to see if there was any channeling going on. Didn't help. Did the same with the cation. didn't help. Replaced the anion resin. Didn't help.
Took the housings off to see if they had mold growing or something, they look clean.
It's been set up for years and working fine, so it's not an installation issue.
Does DI resin go bad in a sealed bag? This anion resin was 2 years old, but still sealed.

I also swapped the TDS probes out and got the same reading.

Also, the TDS is 0 after the mixed bed, so it's not something coming through my water that DI can't remove..
 
Coral reefer said:
I do think there is a shelf life. What kind of sealed bag was it in?
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Like this
20221005_205802.jpg


I tried a third sealed bag, only 1 year old. Same thing. This makes no sense...

Just put the mixed canister in place of the anion, and it's reading zero... Soooo I guess something is up with my anion resin... Seems odd that 3 separate bags are bad....
 
Was the resin damp and stinky? Once I used some I thought I had sealed up well but it was dry, lacked that smell, and did not work.
 
MolaMola said:
Do you have an extra refillable canister that you could try to be sure there's not a problem there?
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I'll have to look again tomorrow, but I don't think I do. That's really the only thing left, but I don't really see what could have failed on the canister. This is really confusing...
 
Srt4eric said:
Faulty tds meter? Or maybe sj has worse than normal water.
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Swapped the probes and got the same result. Mixed bed is still taking it to zero, even when I moved the mixed bed into the anion position.

So it's either the anion resin, or somehow the cartridge.

The cartridge is the only thing I haven't actually changed out (I don't have another one on hand) but I can't really see how the cartridge would be causing this. It's like the water is bypassing the cartridge. But I can see the water flow up through the cartridge, and there is an air gap at the top of the outer canister, so water shouldn't be bypassing that way (if for instance the seal at the top of the cartridge wasn't sealing.)
 
According to color change, cation is nowhere near spent. Also, since this has been happening, my mixed bed has started to get depleted. I believe the color change resin in mixed bed is the anion resin, which leads me to believe it's the anion stage that is not working somehow.
20221005_204717.jpg
 
Ahh, the "pro" mixed is cation and the normal is anion? That's weird. But ok, so maybe my cation resin has gone bad even though it hasnt changed color? Definitely possible, but still seems weird that the TDS wouldn't go down some with the anion resin, since anion seems to be the one that is normally doin the work (depleted fastest)
 
Coral reefer said:
I use cation pretty quick but basically no anion
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Interesting. I have had that cation and mixed cartridge running for probably close to 2 years, and you can see how little it has changed color. I have probably changed anion 4-5 times in that period. Have always had 0tds after the cation/anion stage.

Maybe something recently changed in my supply water that cation removes, and my cation resin is aged out.

I'll look into this more. Thanks!
 
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