Differences between dual di canister setups?

[mfinn]

I have been debating the idea of going to a dual di resin setup on my rodi unit and I think I may have a CO2 problem with my water and have been going through alot of di resin lately.
Looking at the Bulk Reef Supply web page there is a dual di resin set up called the "Dual DI Phosphate CO2 & Silica Eliminator".
With the instructions it says to use Pro Series Anion Di Resin and Pro Mixed Bed Cation Di Resin.
My question is, will you get better and more clean water from this setup, ( per resin refill) over using just the regular dual canister and regular di resin?
There is no difference in price, so what's going to work better?

 

[Actuarious]

They both will work the same in so far as output 0 TDS. The issue is which is more economical. With high CO2 the Anion will be used up faster and with a whole cartridge (Pro) instead of a mix cartridge (regular) it will last longer. Plus with the Pro setup you will not be throwing away some of the good Cation that you will with the regular setup.

 

[Mortie31]

Out of curiosity where is the high co2 coming from? surely your RO system is closed to the air?

 

[mfinn]

They both will work the same in so far as output 0 TDS. The issue is which is more economical. With high CO2 the Anion will be used up faster and with a whole cartridge (Pro) instead of a mix cartridge (regular) it will last longer. Plus with the Pro setup you will not be throwing away some of the good Cation that you will with the regular setup.

Not sure I follow you.
All 3 types of resin cost the same, so if I'm replacing the anion just as fast ( or faster?) as the mixed bed resin, then there is no savings?

 

[mfinn]

@Bulk Reef Supply
@randyBRS
@Ryanbrs

 

[Actuarious]

Not sure I follow you.
All 3 types of resin cost the same, so if I'm replacing the anion just as fast ( or faster?) as the mixed bed resin, then there is no savings?

Sorry meaning to say high CO2 water will remove the Anion faster. So in a mix bed ~60% is anion. That will deplete much faster than a full 100% anion canister. When the mix bed depletes there will probably be good cation that you will need to throw away.

 

[mfinn]

Sorry meaning to say high CO2 water will remove the Anion faster. So in a mix bed ~60% is anion. That will deplete much faster than a full 100% anion canister. When the mix bed depletes there will probably be good cation that you will need to throw away.

That part makes sense.

But doesn't that put extra strain on the cation in the second container which is actually a mixed bed resin?

 

[Actuarious]

That part makes sense.

But doesn't that put extra strain on the cation in the second container which is actually a mixed bed resin?

I wouldn't say extra strain. It is just a more efficient use of resin. The goal is to replace the resin when almost 100% has been used. So you don't want to throw away good anion/cation resin. Every system is different, and if you have high CO2 that is putting a lot of strain on the anion. So in theory you want to have more anion in your DI system.

 

[mfinn]

Thoughts @Bulk Reef Supply ?

 

[chipmunkofdoom2]

A mixed-bed resin contains both cation and anoin resins. Depending on the mix of ions in your water, one might get used up before the other. Let's say you have more negative ions in your water than positive ions. That means the anion beads in the mixed-bed resin will get used up before the cation beads. The result is that your TDS will start rising above zero because the anion is exhausted, and negatively charged ions are getting through. As a result, you'll need to replace your resin. But, since your water contains lower amounts of positively charged ions, your cation resin is still good. Essentially, you're throwing out good cation resin simply because the anion resin is exhausted.

By splitting up the resin and running a single bed, you can replace only the resin you need to. If CO2 eats up your anion resin, no matter. Simply replace the anion resin. The cation resin will likely remain untouched. I switched to a triple DI setup a few months ago (single bed cation, single bed anion and mixed bed). The results have been pretty remarkable. My anion resin is almost 2/3 used up, while the cation and mixed beds haven't even changed colors in the slightest. It was expensive to add another canister and buy all new resin, but I'm almost sure I'm going to be saving money in the long run by not throwing out good resin.

 

[mfinn]

By splitting up the resin and running a single bed, you can replace only the resin you need to. If CO2 eats up your anion resin, no matter. Simply replace the anion resin. The cation resin will likely remain untouched. I switched to a triple DI setup a few months ago (single bed cation, single bed anion and mixed bed). The results have been pretty remarkable. My anion resin is almost 2/3 used up, while the cation and mixed beds haven't even changed colors in the slightest. It was expensive to add another canister and buy all new resin, but I'm almost sure I'm going to be saving money in the long run by not throwing out good resin.

I understand all of the reasons what each resin does.
My question was, does it save money by going with the separate anion and cation canisters, vs a regular dual mixed bed di setup.

With the regular dual mixed bed resin setup, the first container gets used up. Then you move the second container into the first containers place and replace one container of mixed bed resin.
Same with the separated resin setup.
The price of the mixed bed resin is the same as both of the separated resins.
So it doesn't matter price wise.
Is one cheaper to run vs. the amount of water produced?

I also realize every water system is different and will produce different results.
I'm wondering what the general trend is.

 

[Actuarious]

As an example. Lets say all of your TDS will be removed by anion resin, and a full 100% anion canister can produce 100 gallons of 0 TDS water. Using the mix bed may only get you 60 gallons of 0 TDS water. So you get 40 more gallons using the pro under this example.

If your TDS is in exact ratio of what is in the mix bed, then the regular setup is great. Since not everyone knows the exact ratio, being able to see which is depleting and buying only what is needed is good for some.

 

[Ryanbrs Verified Sponsor]

Not sure I follow you.
All 3 types of resin cost the same, so if I'm replacing the anion just as fast ( or faster?) as the mixed bed resin, then there is no savings?

With a standard mixed bed which has you throw it out when the anion portion is depleted, the cation might only be 30% depleted so you are throwing out 70% of the fully charged cation resin. By running them separately, you are only changing the one that's actualy depleted when it is depleted and getting 100% use out of both. The final polish with the mixed bed after should last a very very long time because there are minimal contaminants entering it.