Chloramine removal for rodi system

[moretor1]

Recently ordered a rodi system off of chewy for a good price.

Come to find out that Chloramine will destroy the membrane unless I remove it with a seperate filter first and my water company primarily uses it

When searching for "chloramine filters" 2 kinds show up.

A catalytic carbon chloramine filter that remove ~95% of chloramine Costs about $30 plus the canister cost

Or I can get 2 activated carbon canisters that remove ~88% of chloramine and daisy chain them together for half the price and a theoretically better performance

Is there something I'm missing here? I understand that it might take a slight pressure hit but I don't really care about GPD as this is for small changes and topping off

If anything will 2 prefilters help extend the life of my membrane?

 

[TangerineSpeedo]

You will need to run a dual 1 micron carbons before the RO membrane if you have chloramines. (most cities use chloramines now apparently). Run a prefilter, two carbons then your RO membrane followed by a mixed bed DI resin.

 

[Pod_01]

Come to find out that Chloramine will destroy the membrane unless I remove it with a seperate filter first and my water company primarily uses it

The subject comes up and it seems those canisters just make more $$$ for the supplier or you can consider it make feel good tax.

I would be interested in knowing how the chloramine carbon block works differently compared to the non-chloramine carbon block.
The real science behind it, assuming there is one. Not the science fiction type or marketing type.

I been using 2 regular carbon blocks before the membrane.

 

[Malum Argenteum]

A catalytic carbon chloramine filter

This is what I used when I moved to a city that used chloramine after wrecking a couple membranes. I don't recall if I had tried doubling up on regular carbon block prefilters, but the catalytic GAC worked well for me.

 

[Randy Holmes-Farley]

In my tests, ordinary carbon filters removed chloramine in nearly every case.

 

[KStatefan]

Some of the brands of filters show specs for Chlorine and Chloramine removal

 

[Malum Argenteum]

Specific chloramine prefilters do much better:

 

[Pod_01]

Some of the brands of filters show specs for Chlorine and Chloramine removal

If I am reading that correct the 32-250-10 filter can produce 1000 gal of water before it needs replacement. Ah but this is water going through it so it needs to be divided by the membrane efficiency…
So two sounds like a good idea…

Thanks for the information,

From my readings the manufacturers claim that the catalytic carbon chloramine filter removes 4x more under ideal lab conditions compared to regular carbon filters. Not sure what the ratio under home/ non ideal use is and I was not able to find any 3rd party data.

 

[KStatefan]

If I am reading that correct the 32-250-10 filter can produce 1000 gal of water before it needs replacement. Ah but this is water going through it so it needs to be divided by the membrane efficiency…
So two sounds like a good idea…

Thanks for the information,

From my readings the manufacturers claim that the catalytic carbon chloramine filter removes 4x more under ideal lab conditions compared to regular carbon filters. Not sure what the ratio under home/ non ideal use is and I was not able to find any 3rd party data.

Yes so a 100 gpd system would use 500 gpd if running at 4:1. That rating is also at .5 gpm if you are running slower the capacity would be greater.

I think two carbon blocks are a good idea for anyone on treated water supply or change to a 20" filter. My provider does not use chlormines but could change at anytime without notification.

 

[moretor1]

Some of the brands of filters show specs for Chlorine and Chloramine removal

Not to be a hater but I genuinely don't understand how chloramine reduces the filter life by 12x

I mean isn't chloramine larger and less strongly bonded than free chlorine?

I know they do reduce them but I'd love to see an actual independent study and not one funded by the filter company

 

[Pod_01]

I genuinely don't understand how chloramine reduces the filter life by 12x

The same with the catalytic carbon chloramine filter :

I am sure there is scientific explanation.

Probably related to the ammonia :

Would be nice to know….

 

[Randy Holmes-Farley]

Not to be a hater but I genuinely don't understand how chloramine reduces the filter life by 12x

I mean isn't chloramine larger and less strongly bonded than free chlorine?

I know they do reduce them but I'd love to see an actual independent study and not one funded by the filter company

While I do not generally thing special chloramine filters are needed, why could it not be the case that chloramine damaged a ro filter faster than chlorine?

 

[moretor1]

While I do not generally thing special chloramine filters are needed, why could it not be the case that chloramine damaged a ro filter faster than chlorine?

I dont disagree that it damages the ro membrane more. I'm not exactly sure how that chemistry works
I dont exactly know if chloramine "spends" more carbon than a similar amount of chlorine would.
I guess my real qualm is whether catalytic carbon is actually worth the price in a lifespan/cost sense

 

[Randy Holmes-Farley]

I dont disagree that it damages the ro membrane more. I'm not exactly sure how that chemistry works
I dont exactly know if chloramine "spends" more carbon than a similar amount of chlorine would.
I guess my real qualm is whether catalytic carbon is actually worth the price in a lifespan/cost sense

I do t really know the reactivity of chloramine vs chlorine on ro filters, but imo, no one should buy fancy chloramine filters for Their systems unless normal ones are not getting the job done.

 

[Pod_01]

I do t really know the reactivity of chloramine vs chlorine on ro filters, but imo, no one should buy fancy chloramine filters for Their systems unless normal ones are not getting the job done.

Randy what I am curious about, why does chloramine use up the carbon block 12x faster compared to chlorine?
For example the manufacturer data claim that the carbon block can treat 45000 gallons of water with chlorine but only 4000 gallon with chloramine…
Just curious, I suspect it is the ammonia in the chloramine but…

 

[Randy Holmes-Farley]

Randy what I am curious about, why does chloramine use up the carbon block 12x faster compared to chlorine?
For example the manufacturer data claim that the carbon block can treat 45000 gallons of water with chlorine but only 4000 gallon with chloramine…
Just curious, I suspect it is the ammonia in the chloramine but…

I do not know the answer to that, or even if those numbers are accurate, but let’s assume they are.

Chloramine is naturally more stable than chlorine, which is why it is used, so maybe it takes more breakdown ability in the carbon block.

For example, if a block treated 4000 gallons of chloramine water and was at the end of its life, could it still treat a lot of chlorine water? Maybe, if chlorine is just easier to breakdown, and maybe not if the chloramine itself was damaging the block more than chlorine does.

 

[KStatefan]

Not to be a hater but I genuinely don't understand how chloramine reduces the filter life by 12x

I mean isn't chloramine larger and less strongly bonded than free chlorine?

I know they do reduce them but I'd love to see an actual independent study and not one funded by the filter company

I do not know but assumed it had to do with it being more stable. Other brands also rate them greatly different between chlorine and chlorimine the pentek is even greater.

If you use specs from Matrikx the "expensive" cartridge cost less to operate.

 

[Buckeye Hydro]

While I do not generally thing special chloramine filters are needed, why could it not be the case that chloramine damaged a ro filter faster than chlorine?

At least for Filmtec membranes, the tolerance for contact with chloramine is much higher (as in 300x) than chlorine. However where there is chloramine, there is also free chlorine.

 

[Buckeye Hydro]

Another fun fact to know and tell: be careful in interpreting for instance, the Chlorine Capacity of carbon blocks. Testing protocols are all over the board - Matrix was one of the few that followed the correct testing methods. Also know that stated chlorine capacity is typically the cumulative flow at which point 50% of the chlorine is getting through. The devil is in the details here, so you have to read and understand the fine print - if you can even find that information.

 

[KStatefan]

Another fun fact to know and tell: be careful in interpreting for instance, the Chlorine Capacity of carbon blocks. Testing protocols are all over the board - Matrix was one of the few that followed the correct testing methods. Also know that stated chlorine capacity is typically the cumulative flow at which point 50% of the chlorine is getting through. The devil is in the details here, so you have to read and understand the fine print - if you can even find that information.

So this thread got me looking more into my carbon selection based on the cost in my spreadsheet above and I am going to change what I use in the future and switch out my workman with chlorguard.