Strange result with 4 stage DI setup

[gobble]

Since I had 4 canisters, I put together a series of DI resin that goes cation, anion, mixed bed cation, regular mixed bed. I thought this would be the ultimate setup.

The strange thing is the final mixed bed resin was used up first (I thought I’d rarely need to change that one).The other canisters maybe have a inch or two of color change in them. This tells me there must be a decent amount of TDS sneaking through the mixed bed cation.

How is this possible?

 

[gobble]

I think I figured out my problem but it results in more questions. I moved my meters around and found that TDS coming out of the RO membrane was 2. TDS coming out of the cation resin was 10! However, the cation resin was still purple, a darker purple than fresh resin though.

Does the color changing cation resin not change to a yellow color like the others??? Is there just a subtle change from light purple to dark purple? Is the only way to know it's depleted to have a meter in place?

I now have TDS of 2 off the RO, 1 off the cation and 1 off the anion.

Does the anion resin change color? The bottom 2 inches or so are yellow. Can I keep this resin in place until the entire cartridge is yellow or should I be getting 0 TDS after the anion?

If BRS reads this thread I'd really like to know the answers to these questions.

 

[Rispa]

@Bulk Reef Supply

 

[gobble]

at bulk reef supply? That makes no sense.

 

[Rispa]

at bulk reef supply? That makes no sense.

I tagged them, so it will show up in their feed and they are more likely to see it.

 

[gobble]

Oh, that must be a twitter thing. If so I don't understand but thanks.

 

[Rispa]

Oh, that must be a twitter thing. If so I don't understand but thanks.

It is, but it also works on here Give it a try. Type @ then add in the first few letters of someone's name. A list of all related names should pop up. You can click the one you intend and when you post it should show up as a blue link and tag the person.

 

[gobble]

Change to what I wrote above. The new cation is outputting 8 TDS after running for a while. 2 TDS then out of the anion and the final mixed bed is being used up pretty quickly. Output TDS from the RO membrane is only 2.

 

[gobble]

Unless someone can prove me wrong, I don't think the BRS pro series resins perform as advertised.

After 30 gallons of water -

output water from RO membrane = 2 TDS
output water from NEW pro series cation resin = 10! TDS
output water from anion resin = 2 TDS
output water from pro series mixed bed (still blue/purple color) = ? don't know
output water from regular mixed bed = 0 TDS

However, 1/3 of the regular mixed bed resin was used up in 30 gallons of water when the output water from the RO filter was 2 TDS!!! This is consistent with the usage back when I was simply using only regular mixed bed resin. I don't believe the pro series cation/anion/mixed bed is helping at all.

What's going on?

 

[JoshH]

@randyBRS #Reefsquad any thoughts here? The only thing I can think of is the cation resin is creating new ions by changing there original charges.. But that's beyond what I know for sure. Do you run off city water or a Well?? There might be something else in your water that the resins aren't able to remove individually.

 

[TheEngineer]

Sounds like a telltale sign of high CO2. Any chance this is off of a well?

 

[MTBake]

I use the pro series resin also but don't have this issue. I get 8 tds after ro and 0 after the anion stage. Also get 0 tds after the mixed bed. I do not have a 4th stage after the pro series mixed bed.

Sounds like it could be high co2. Are you on a well? Or city supplied water?

 

[gobble]

I am on a well. What I find strange is my consumption of the final mixed bed seems to be the same with or without the cation/anion/pro mixed bed in front of it. Assume my co2 is high (and I've never measured it), would that make the pro series stuff ineffective? I didn't notice this problem at first, just the last few batches of making water. Does co2 increase during the summer months?

 

[Rispa]

@Randy Holmes-Farley

 

[TheEngineer]

Do you have a pH test kit? You can do a bubble test to see if you have high CO2.

 

[gobble]

I do not but will look into that after the holiday. Time to go wakesurfing.

 

[Randy Holmes-Farley Verified Community Expert]

Unless someone can prove me wrong, I don't think the BRS pro series resins perform as advertised.

After 30 gallons of water -

output water from RO membrane = 2 TDS
output water from NEW pro series cation resin = 10! TDS
output water from anion resin = 2 TDS
output water from pro series mixed bed (still blue/purple color) = ? don't know
output water from regular mixed bed = 0 TDS

However, 1/3 of the regular mixed bed resin was used up in 30 gallons of water when the output water from the RO filter was 2 TDS!!! This is consistent with the usage back when I was simply using only regular mixed bed resin. I don't believe the pro series cation/anion/mixed bed is helping at all.

What's going on?

I don't intend to "prove you are wrong", but you may be misusing/misunderstanding TDS in the context of Ro/Di.

When you use cation and anion resins in series, the TDS is EXPECTED to rise after the first one. If it doesn't, it isn't working.

The reason is that the first resin swaps either H+ or OH- for the other ions in the water. Both OH- and H+ have far higher conductivity than any other ions, so when that takes place, the TDS rises, as you observed.

When you pass it through the second one, it then takes out all of the ions in the water, and if neither bed is depleted, the TDS will drop to zero.

How fast any of these DI resins are used up depend on how much TDS and how much CO2 in in the water entering it. The anion resin can be used up rapidly if there is substantial CO2 in the water, and it does not show up very much on a TDS meter.

 

[gobble]

Thanks. I guess what I'll do is swap in new anion resin even though it hasn't color changed and see what reading I get after it. I'd like to think the cation/anion/pro mixed bed is doing some good even though the final mixed bed is depleting rather quickly. I should also T in the meter after the pro series mixed bed and see if I get a reading there.

 

[gobble]

Nobody from BRS wants to comment on why I'm getting a significant amount of TDS through their "pro" series cation/anion/mixed bed resins?

Look at how the final stage regular mixed bed resin is being used up much faster than the earlier resins.​

 

[TheEngineer]

Why not reach out to them directly instead of through a third party forum?