TDS increasing after passing through DI resin…why?!

[fity2pounder]

My setup is:

1. Sediment filter
2. Second sediment filter
3. Carbon block
4. Second carbon block
5. First TDS meter reads about 400
6. RO membrane
7. Second RO membrane using the waste from the first
8. Second TDS meter reads about 6-7 after running for about 10 minutes to flush out the tds creep. The RO membranes seem to be working great as I’m getting about 97-98% filtration. Even after going through TWO RO membranes in series.
9. Cation resin
10. Second cation resin
11. Anion resin
12. Second anion resin
13. Third anion resin
14. Fourth anion resin
15. Mixed bed resin
16. TDs usually reads zero but has now started reading about 8-9

So the issue is that the tds is increasing after passing through many di resin chambers. It’s going from 6 up to 8 or 9.

Ideas of what may be causing it:
1. Would di resin be able to pass through the filters in the cartridges if not packed well enough? And this would cause increased tds as the resin itself is being registered as tds?
2. Could old di resin cause an increase in tds? None of the cartridges are exhausted (only the very first anion is about half exhausted) but some of them have been in there for many months because I have so many (I move them up the line after the very first one exhausts so as to get full use of all the resin and not throw oils any good resin) and because my city water uses almost no cation resin at all.
3. Can old tubing cause an increase in tds? On of my lines just snapped not too long ago as it was very brittle. Could the tubing be flaking off into the water between or after di chambers causing the increase?

Anyone have any ideas or suggestions? I hear that @Randy Holmes-Farley is the man for questions like this. Hope he has a moment to chime in. Thanks in advance for anyone’s help

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[fity2pounder]

Forgot to mention that when I most recently replaced an exhausted anion cartridge that I opened a new bag of anion resin. I’ve read that there is such thing as a bad batch of resin. Is that a thing? How cld I tell? Cld that be the cause?

 

[fity2pounder]

Also…the batteries in the tds meter are relatively new and I also used a handheld tds meter too to double check.

 

[fity2pounder]

As much as it pains me to say it, this was 100% user error. Two issues:

1. I believe this was the primary culprit. The cartridges were not packed well enough. A video I watched showed the cartridges simply being tapped on the table to settle the resin. This is a great starting point, but you should also pack the resin a bit above the top of the cartridge and then smash it down in there SUPER hard. It should be in there so full that it’s almost difficult to put the sponge and cap back on.
2. I took the cartridges completely apart to clean them. When I put them back together I accidentally put a couple of the filters that stop the resin from passing through in upside down. This likely allowed some of the resin to slip through. The filter has a piece of plastic inside of it. That piece of plastic needs to go to the top when the filter is in place in the system. The plastic piece fits together with the opening at the top of the cartridge. You will see they are the same size once installed correctly.

So it’s was as easy as that. Tds almost immediately back down to zero. I also removed a couple of the extra cartridges I had in place because they should no longer be needed as long as I continue to pack the cartridges very tightly. I hope this helps some people out there!!

 

[Buckeye Hydro]

As much as it pains me to say it, this was 100% user error. Two issues:

1. I believe this was the primary culprit. The cartridges were not packed well enough. A video I watched showed the cartridges simply being tapped on the table to settle the resin. This is a great starting point, but you should also pack the resin a bit above the top of the cartridge and then smash it down in there SUPER hard. It should be in there so full that it’s almost difficult to put the sponge and cap back on.
2. I took the cartridges completely apart to clean them. When I put them back together I accidentally put a couple of the filters that stop the resin from passing through in upside down. This likely allowed some of the resin to slip through. The filter has a piece of plastic inside of it. That piece of plastic needs to go to the top when the filter is in place in the system. The plastic piece fits together with the opening at the top of the cartridge. You will see they are the same size once installed correctly.

So it’s was as easy as that. Tds almost immediately back down to zero. I also removed a couple of the extra cartridges I had in place because they should no longer be needed as long as I continue to pack the cartridges very tightly. I hope this helps some people out there!!

I doubt these were the cause of your issue.

Tightly packing the resin is critical primarily with mixed bed resin. You do this in an upflow situation to keep the bed from fluidizing which separates the cation and anion beads by weight.