2 stage DI resin, worth it?

[reef’r]

I have a 4 stage 100gpd RODI unit running the standard mixed DI resin, coming into the resin I’m at 2-3 TDS and out I’m zero. Would there be any advantage to adding another stage of DI? I’m wanting to upgrade my water mixing setup so was thinking of adding another stage of DI just not sure I would gain any benefit and before I make the purchase just wanted to ask here. Thank you

 

[Crabs McJones]

If you're already getting 0 out of your one DI, I don't see a need for a second one.

 

[exnisstech]

I run a second di stage. I run mixed bed but not color changing. I like having the second di stage so I don't have to constantly monitor the TDS and stop production when the first is depleted. When the first is depleted I rotate the last di cartridge into the first canister and add a new refill to the last stage. I just like being able to change stuff out at my convenience.

 

[ryshark]

I run a second di stage. I run mixed bed but not color changing. I like having the second di stage so I don't have to constantly monitor the TDS and stop production when the first is depleted. When the first is depleted I rotate the last di cartridge into the first canister and add a new refill to the last stage. I just like being able to change stuff out at my convenience.

I do the same. I’ve thought about getting a 3rd stage and definitely wouldn’t run just 1. By the time it reads 1ppm, it’s too late, if you only have 1 stage. Before 1ppm is probably .5, .75, .9 etc.

 

[edsbeaker]

I run a second di stage. I run mixed bed but not color changing. I like having the second di stage so I don't have to constantly monitor the TDS and stop production when the first is depleted. When the first is depleted I rotate the last di cartridge into the first canister and add a new refill to the last stage. I just like being able to change stuff out at my convenience.

I do the same. I’ve thought about getting a 3rd stage and definitely wouldn’t run just 1. By the time it reads 1ppm, it’s too late, if you only have 1 stage. Before 1ppm is probably .5, .75, .9 etc.

I also run 2 DI canisters. I feel that this way I can get every bit out of the resin in the first inline since I have the second as backup. Then when fully exhausted I move the newer one to replace the older and refill.

 

[KrisReef]

3 X stages make zero TDS water the same as a single stage but having 3 allows for more time between failure and also allows rotation of stages to avoid extinction of DI TDS eruptions.

Refill responsibly :smiling-face-with-sunglasses:

 

[Derrick0580]

I run separate cat ion and an ion then a mixed bed and never worry about tds!

 

[fish_collector]

I run separate cat ion and an ion then a mixed bed and never worry about tds!

This is what I use.

I wish my post membrane was 2-3, I'm at 25 on a good day with a filmtek membrane.

 

[dank.reefer]

I run a triple DI set up and it is totally worth it. The first chamber is Cation resin, the second Anion, and thr third is mixed bed. With this set up after processing easily 1000g I have not used up any of the Cation resin or the mixed bed. Also the Anion resin lasts longer since it us a pure Anion bed instead of a mix.

 

[reef’r]

I think I’ll go ahead and add a second stage of DI resin for the reasons mentioned above. I don’t make a ton of water but just want to be sure when I do it’s as good as possible

 

[Mels_Reef]

I think I’ll go ahead and add a second stage of DI resin for the reasons mentioned above. I don’t make a ton of water but just want to be sure when I do it’s as good as possible

You won’t regret it. You can be confident that your tds is always zero. When the second chamber gets half way used up, move it to the first position and then refill the cartridge for the second position. You’re guaranteed to always have 0 tds and you always fully exhaust all your resin. So no waste….

 

[Randy Holmes-Farley Verified Community Expert]

I run a second di stage. I run mixed bed but not color changing. I like having the second di stage so I don't have to constantly monitor the TDS and stop production when the first is depleted. When the first is depleted I rotate the last di cartridge into the first canister and add a new refill to the last stage. I just like being able to change stuff out at my convenience.

Yes, I do that too, and you end up using less DI resin over time since you can more fully use each cannister in turn.

 

[fish_collector]

The initial cost of separate cation and anion resins is more, but for the long haul it's money well spent. Most of the activity is with the anion resin. When you buy mixed bed resin, you're really only going to use up half of it before you begin to see TDS again because the cation part was never used up. But in the OPs case with very low TDS to begin with, quality mixed bed resin would last seemingly forever lol.

The mixed bed resins sold on Amazon are pure junk, I'd go so far as to say they're used resins that have been regenerated as their capacity isn't very good. I bought some mixed bed resin from BRS and it lasts multitudes longer before I see TDS again. I ended up also adding cation and anion resins to my rodi because of my high TDS. I've added a second membrane as well and have been playing with it to see what configuration gives me the best results. Next step is a booster pump to see if I can get my product TDS down some.

 

[Randy Holmes-Farley Verified Community Expert]

The initial cost of separate cation and anion resins is more, but for the long haul it's money well spent. Most of the activity is with the anion resin. When you buy mixed bed resin, you're really only going to use up half of it before you begin to see TDS again because the cation part was never used up.

I think that is not always true. If there is significant CO2 in the water, then yes, the anion depletes faster as carbonate gets bound, although many mixed bed are not 1:1 to begin with.

But not all water has substantial CO2 in it. My water (MWRA in Boston area) has very little.

 

[Vincenc]

I run 3 stage DI cation,anion, mixed bed.
I run it on well water. Do not remember last time I changed Cation. Anion is a different story. I change that one about every 500gal. Mixed bed rarely change.

 

[BryanM]

I think I’ll go ahead and add a second stage of DI resin for the reasons mentioned above. I don’t make a ton of water but just want to be sure when I do it’s as good as possible

I run cation and anion separately now, as usually one depletes much faster than the other, and I clearly have to replace anion far more than cation.

 

[Dburr1014]

I have a 4 stage 100gpd RODI unit running the standard mixed DI resin, coming into the resin I’m at 2-3 TDS and out I’m zero. Would there be any advantage to adding another stage of DI? I’m wanting to upgrade my water mixing setup so was thinking of adding another stage of DI just not sure I would gain any benefit and before I make the purchase just wanted to ask here. Thank you

Are you on a well?

I run separate cat ion and an ion then a mixed bed and never worry about tds!

This is what I do. I have CO2 in my well so the anion gets burned up pretty quick. I probably get 150 gallons and then I recharge the anion. Takes me about 45 minutes to recharge and get the system back up and running. I'm on the same anion beads for like three or four years now.

 

[reef’r]

Are you on a well?

This is what I do. I have CO2 in my well so the anion gets burned up pretty quick. I probably get 150 gallons and then I recharge the anion. Takes me about 45 minutes to recharge and get the system back up and running. I'm on the same anion beads for like three or four years now.

Nope city

 

[TastesLikeChicken]

Mine came with 2 DI cartridges so that’s all I know.

If your upgrading thing consider adding a second RO membrane to double the water production.

 

[fish_collector]

I think that is not always true. If there is significant CO2 in the water, then yes, the anion depletes faster as carbonate gets bound, although many mixed bed are not 1:1 to begin with.

But not all water has substantial CO2 in it. My water (MWRA in Boston area) has very little.

We will be moving to a home that is on a well in a year perhaps. It is stated in our shared well agreement that the water will need to be tested at least yearly so I'll wait until the time is closer to worry about it. If a test indicates excessive CO2, what would be the steps to de-gas it before sending it to the RODI?