Playing with different di resins

[mfinn]

For a while now it seems like I have been going through alot of di resin in my ro/di unit.
I think part of it is because of CO2 in my water.
I've been asking a few questions and one thing that was said here,
https://www.reef2reef.com/threads/differences-between-dual-di-canister-setups.363452/
was that anion resin would CO2 out of the water.
So my thought was to add a 3rd canister to my dual mixed bed resin setup and use anion resin in it.

So I added it and put various tds meters to see what results I'm getting and I'm wondering if it was a mistake.
I use a spectrapure 99% membrane so I've always gotten a tds reading of 2 out of the membrane.
Once in a great while it will bounce up to 3 but usually goes down to 2.
My incoming water this morning was 56-57.

So after setting up the 3rd resin canister and letting it run for a hour, I turned on the tds meters and this is what I see.



This is what confuses me.
The tds coming out of the ro membrane and going into the first canister which is the anion resin is 2.
But the tds after the anion has gone up to 5. What the??

I figured that if anything it would go down.
Shouldn't it?

But go up?

This morning the dual tds meter was plugged into the line coming out of the ro membrane and it said 2.
The single tds meter I have there now also says 2. So I'm going with the idea that it is accurate. At least accurate enough for this use. So I'm assuming the tds reading of 5 is also accurate.

 

[ndrwater]

This is really interesting.. knowing what testing BRS did in their video series, makes me wonder if @randyBRS would chime in here..

 

[mfinn]

This is really interesting.. knowing what testing BRS did in their video series, makes me wonder if @randyBRS would chime in here..

I'm hoping so.

 

[Reef-junky]

I thought I read somewhere that u should run an air stone in water with high CO2 before Di so you don’t burn it up as fast. You would have to collect your RO water then pump it through the DI after you ran an air stone in it for a while.

 

[mfinn]

I thought I read somewhere that u should run an air stone in water with high CO2 before Di so you don’t burn it up as fast. You would have to collect your RO water then pump it through the DI after you ran an air stone in it for a while.

I've read that too, but I don't have the room or the desire to do that.

 

[JoshH]

There was something mentioned in one of the BRS videos about how when running single bed resins you can see an increase in TDS after each stage due to the reactions between positive and negatively charges ions and positive or negatively charged resins. This is why they always suggest the mixed bed final polish at the end of single bed canisters. The theory is that new molecules form which increases the over TDS but the newly formed molecules are easier to remove than there previous forms which means that while it temporarily increasing the TDS that TDS is easier to remove and isn't as hard on the Resin. I'll have to dig the video up but I'm sure it's the one talking about the benefits of running single bed resins. You could run a degassing setup to help eliminate the CO2 and just size it for your average water change vs long term storage to help save space. Or if you have the money, a degassing cylinder...

 

[Reef-junky]

https://www.reef2reef.com/threads/diy-co2-degassing-chamber-for-ro-di.212587/

https://www.aquaticlife.com/blog/how-co2-can-impact-di-resin-consumption/

 

[cromag27]

cation removes almost all positively charged ions except hydrogen. anion will remove negatively charged ions and what you have left is hydrogen hydroxide (yummy water). don’t think it will work well in reverse order and that could result in burning through your cartridges.

have you test your co2 level? are you on a well?

 

[dugthefish]

Slight detour, but.....15 years ago everyone I knew just used tap water/dechlorinator. I know 0 TDS is ideal, but are we splitting hairs trying to get from 99.5% pure up to 100%?

 

[mfinn]

Slight detour, but.....15 years ago everyone I knew just used tap water/dechlorinator. I know 0 TDS is ideal, but are we splitting hairs trying to get from 99.5% pure up to 100%?

Yes, alot of us did use tap water 15 years ago ( or more) . I was one of them.
At the time my tap water TDS was in the 25 TDS range. For years it was like this.
Every once in a while I would check just to be sure. I noticed over time that the TDS in my tap water was slowly increasing. Right now it's at 57. Last summer it was near 70.
Then the final straw was when my water company decided to add chlorine.
So I decided to go with a ro/di unit.
The first 10 years or so I could make a single canister of mixed bed resin go 5-6 months and make several hundred of gallons of 0 TDS water.
Maybe I got spoiled and now am trying to get more water for my $ spent.
I started to notice last spring that the TDS coming out of the ro membrane was going up to 3 and 4 and my di resin was being depleted at a fairly fast rate.

So this was my attempt at solving that issue.

My only question was why did the TDS go up after going through anion resin.
I believe @JoshH answered that as well as @cromag27 with additional info.
Thank-you guys.

At this point I have no desire to try and de-gas the water.
Like I said earlier I don't have the room or even want to.

 

[Reef-junky]

The problem with tap water is unless you have a report which I think you can get them you don’t know what your adding to your tank. There are so many things are in drinking water it’s just not worth the risk. There’s a reason people stopped using tap water.

 

[mfinn]

The problem with tap water is unless you have a report which I think you can get them you don’t know what your adding to your tank. There are so many things are in drinking water it’s just not worth the risk. There’s a reason people stopped using tap water.

Tap water wasn't even part of this thread.

 

[scottedontknow]

It seems your order of canisters is off. Mixed bed should indeed be last. I run..
Cation->anion-> mixed bed then because rodi water had an interesting smell I added another carbon block after the mixed bed. I like you see an increase (from 0tds to 1tds) going between cation and anion then back to 0tds after mixed bed. My di resin lasts soooooo much longer now! If only I can get my sediment block to last longer [emoji23][emoji23][emoji23][emoji23]

 

[scottedontknow]

Sediment filter-> carbon block-> carbon block-> cation-> anion-> mixed bed-> carbon block


Please excuse my awful laundry room (second to last room left to renovate haha)

 

[mfinn]

It seems your order of canisters is off. Mixed bed should indeed be last. I run..
Cation->anion-> mixed bed then because rodi water had an interesting smell I added another carbon block after the mixed bed. I like you see an increase (from 0tds to 1tds) going between cation and anion then back to 0tds after mixed bed. My di resin lasts soooooo much longer now! If only I can get my sediment block to last longer [emoji23][emoji23][emoji23][emoji23]

I didn't go the traditional route.
I only used the anion resin as a attempt to deal with some co2 that I suspect I have.
I know there are more traditional ways to deal with co2.
Then after the anion resin, I have a dual mixed bed resin setup.
This was just a experiment, that failed.
I am just going to go back to a dual mixed bed resin setup, and be thankful my water is as good as it is.
It could be worse. Much worse.

 

[mfinn]

Just going to eliminate the top canister.

 

[scottedontknow]

Did you try 3 stage? If so were you plowing through resin?

 

[cromag27]

It seems your order of canisters is off. Mixed bed should indeed be last. I run..
Cation->anion-> mixed bed then because rodi water had an interesting smell I added another carbon block after the mixed bed. I like you see an increase (from 0tds to 1tds) going between cation and anion then back to 0tds after mixed bed. My di resin lasts soooooo much longer now! If only I can get my sediment block to last longer [emoji23][emoji23][emoji23][emoji23]

go larger micron. downside is you’ll foul the downstream filters faster. sediment aren’t very expensive so i only use .5 micron.

 

[Reef-junky]

Tap water wasn't even part of this thread.

Oh really

I’ll leave you to your post which you already have been told the the solution to more then once.

Slight detour, but.....15 years ago everyone I knew just used tap water/dechlorinator. I know 0 TDS is ideal, but are we splitting hairs trying to get from 99.5% pure up to 100%?

Yes, alot of us did use tap water 15 years ago ( or more) . I was one of them.
At the time my tap water TDS was in the 25 TDS range. For years it was like this.
Every once in a while I would check just to be sure. I noticed over time that the TDS in my tap water was slowly increasing. Right now it's at 57. Last summer it was near 70.
Then the final straw was when my water company decided to add chlorine.
So I decided to go with a ro/di unit.

 

[mfinn]

Did you try 3 stage? If so were you plowing through resin?

No, I didn't.
I've seen most of the threads where the benefits were talked about.
One thing I did not see is , what are the cost savings by going with the 3 stage method?
Are you getting more gallons of 0 tds water for the same amount of money spent?


@Reef-junky thank-you for your input and advice.
But as I said it before, I was simply looking for a answer to why the tds went up after the anion resin.
I've known about the de-gassing methods for a while and I personally do not want to go that direction.

The slight detour that was mentioned, was only that.