Can Chloramines get past a good RO/DI

[LostInTheDark]

There is a lot of contradictory information out there about Chloramines and RO/DI. If I have a good working RO/DI with catalytic carbon, can Chlorine/Chloramine get past the RO stage. As a follow up. If the carbon gets exhausted will the Chloramines show up on a TDS meter and will it get absorbed by the DI resin?

 

[stunreefer]

There is a carbon filter made specifically for removing chloramines. Definitely want to add one if you're facing chloramines to protect other filters. This can replace existing carbon, or be added downstream.

 

[AllSignsPointToFish]

No, not unless the filters are not performing correctly. The activated carbon should easily remove chloramines, but even if the carbon doesn't get it, the RO membrane should take it out.

The chloramines will probably not show up as TDS as they are not a dissolved salt. However, if the chloramines dissociate in aqueous solution, the DI resin (i.e., cation/anion resin) will remove them.

 

[LostInTheDark]

No, not unless the filters are not performing correctly. The activated carbon should easily remove chloramines, but even if the carbon doesn't get it, the RO membrane should take it out.

The chloramines will probably not show up as TDS as they are not a dissolved salt. However, if the chloramines dissociate in aqueous solution, the DI resin (i.e., cation/anion resin) will remove them.

So. Simple answer. I should be fine as long as I keep my carbon current and the Membrane is working up to specs. Thanks This makes sense. There just seems to be a lot of scare talk out there from some manufacturers and reefers about Chloramines getting through everything but a brick wall.

 

[M3ace9]

The cloromines will not show on your tds meter since it is not a dissolved solid but in fact a chemical added at your water treatment plant. In fact there is not real way to test for it. Yes the carbon block will filter it but only for so long. The cloromines reduce the life of a regular carbon block by 60 if I recall. Reason is the chloromines have trace ammonia which needs to removed. I live in California and this is a big issue at the beginning of summer since the county dumps the stuff in the water to get ready for the summer water usage. My .02 would be to run chloromine blocks for sure.

 

[LostInTheDark]

There is a carbon filter made specifically for removing chloramines. Definitely want to add one if you're facing chloramines to protect other filters. This can replace existing carbon, or be added downstream.

Yep. I have 2 carbon stages now and am adding a second catalytic carbon stage just to be sure. That will give me a total of seven stages. Pre-filter, 3 carbon, RO and 2 DI. Lets see it get through that.

 

[M3ace9]

So. Simple answer. I should be fine as long as I keep my carbon current and the Membrane is working up to specs. Thanks This makes sense. There just seems to be a lot of scare talk out there from some manufacturers and reefers about Chloramines getting through everything but a brick wall.

Please note that chloromines are not a solid but a chemical so the carbon is the acting defense not the DI. This subject is always debated because across the nation different water treatment plants use different chemicals to test their water. Call them to see if they use chloromine in their water processing. I was also on the fence until I did some research and put all the info together.

 

[M3ace9]

Yep. I have 2 carbon stages now and am adding a second catalytic carbon stage just to be sure. That will give me a total of seven stages. Pre-filter, 3 carbon, RO and 2 DI. Lets see it get through that.

The catalytic should be the first stage or your regular carbon block will just be destroyed

 

[LostInTheDark]

so the carbon is the acting defense not the DI

This is the main question I guess. Does DI resin absorb Chloramines???

 

[LostInTheDark]

The catalytic should be the first stage or your regular carbon block will just be destroyed

Yes. Thats how I have it set up 2 catalytic then a 1 micron carbon block.

 

[Randy Holmes-Farley]

The cloromines will not show on your tds meter since it is not a dissolved solid but in fact a chemical added at your water treatment plant. In fact there is not real way to test for it. Yes the carbon block will filter it but only for so long. The cloromines reduce the life of a regular carbon block by 60 if I recall. Reason is the chloromines have trace ammonia which needs to removed. I live in California and this is a big issue at the beginning of summer since the county dumps the stuff in the water to get ready for the summer water usage. My .02 would be to run chloromine blocks for sure.

Not true.

A cheap chlorine kit will detect chlormaine, and if you really want to distinguish chloramine from chloramine, you can get a specific chloramine kit.

A good RO/DI will typically remove it without any special filters.

I'd go regular, and if concerned, get a cheap kit to test the effluent before getting special cartridges.

 

[M3ace9]

Not true.

A cheap chlorine kit will detect chlormaine, and if you really want to distinguish chloramine from chloramine, you can get a specific chloramine kit.

A good RO/DI will typically remove it without any special filters.

I'd go regular, and if concerned, get a cheap kit to test the effluent before getting special cartridges.

Yes there are kits for chloromines but to my understanding the amount is in trace amounts and the kits will not be able to detect it. Even though the amounts are trace it is still introduce ammonia into your tank and will continue to throw its balance off. And yes the rodi unit will remove the chloromine but please note that the life of the carbon block is cut significantly. The chloromines are an additional chemical that the carbon block is needing to filter out.

 

[M3ace9]

This is the main question I guess. Does DI resin absorb Chloramines???

No DI does not remove chloromines only the carbon does. Regular carbon removes it just fine but the life of the block is cut substantially. DI only removes dissolved solids not chemicals.

 

[LostInTheDark]

No DI does not remove chloromines only the carbon does. Regular carbon removes it just fine but the life of the block is cut substantially. DI only removes dissolved solids not chemicals.

And when the carbon gets exhausted will the RO membrane remove it?

 

[jason2459]

And when the carbon gets exhausted will the RO membrane remove it?

It will damage the membrane and blow through it. Membranes that we use have 0 tolerance of any kind of chlorine or chloramine.

Edit: here's most Membrane manufacturer's standard disclaimer

Under certain conditions, the presence of free chlorine and other oxidizing agents will cause premature membrane failure. Since oxidation damage is not covered under warranty, Dow Water & Process Solutions recommends removing residual free chlorine by pretreatment prior to membrane exposure. Please refer to technical bulletin "Dechlorinating Feedwater" for more information

And if You look at the spec sheet you will find often 0 or <0.1ppm for tolerance of chlorine.

 

[AllSignsPointToFish]

According to Spectrapure, polyamide membranes are much more resistant to chloramine than free chlorine. While not recommended, most RO membranes can tolerate some chloramines for a while.

 

[jason2459]

According to Spectrapure, polyamide membranes are much more resistant to chloramine than free chlorine. While not recommended, most RO membranes can tolerate some chloramines for a while.

Yet will still get damaged and will blow past. Not recommended at all.

 

[AllSignsPointToFish]

The truth is that your membrane will probably need to be changed for other reasons long before chloramine deterioration is a significant factor.

 

[jason2459]

The truth is that your membrane will probably need to be changed for other reasons long before chloramine deterioration is a significant factor.

I'm not sure about that but open for information on it.

 

[jason2459]

So, from spectrapure and then you'll just exhaust your DI and hope channeling isn't a problem.

More detailed explanation on Chloramines, membranes and carbon filters:

In order to understand the mechanism of chloramine removal, a little background information on the chemistry of chloramines is necessary. Chloramines are formed by the reaction of ammonia and chlorine gas. Chloramines can exist as three chemical species: monochloramine (the predominant species found in tap water), dichloramines and trichloramines. The chloramine species depends upon the pH of the water and the ratios of chlorine to ammonia. At tap water pH levels of 7 to 8.5, the formation of monochloramines is favored. Of the three species, monochloramine is the most stable and difficult to remove, as well as the most damaging to aquatic life.

A “ppm-hour” is defined as the exposure of 1 ppm chlorine/chloramine water for 1 hour. Film-Tec quotes 300,000 ppm-hours (six years at 1 ppm) of chloramine resistance for their TFC polyamide (PA) membrane material, but only 200 to 1000 ppm-hours of free chlorine resistance. This indicates that chloramines will not damage Film-Tec membranes, while free chlorine levels must be held below 0.1 ppm to prevent oxidation damage. The easiest test for chloramine is with a Total Chlorine Test Kit (SpectraPure Part # TK-CL-10). The TK-CL-10 tests for a combination of free chlorine and chloramines. A sample of the wastewater stream from the RO membrane should show no signs of chlorine.

The most important purpose of a sediment filter is to protect the downstream carbon block filters from plugging with sediment. A properly designed sediment filter will have a micron rating smaller or equal to the closest downstream filter element. It will have a gradient density structure such that the outer layers capture the larger particles and the inner layers capture the finer particles. This will maintain a large dirt holding capacity and prevent the finer particles from plugging downstream carbon filters. Using a 5 micron carbon block followed by a 0.5 micron carbon block, maximum chlorine and volatile chemical removal can be achieved without premature filter failure. If a sediment filter is used that passes particles larger than the next downstream filter, that filter will plug, blinding off the active carbon surfaces, reducing its ability to remove chlorine and organic chemicals.

Trade-offs exist in almost any circumstance and carbon filtration is no exception.
The smaller the micron rating, the better the removal capacity due to greater surface area. Carbon block filters made with bituminous carbon are more effective than coconut shell carbon filters for removal of monochloramine. On the other hand, in water supplies with chlorine only, the coconut shell carbon may have higher capacities for the removal of free chlorine and low molecular weight volatile organic compounds such as trihalomethanes (chloroform).

Multi-carbon block pre-filtration is not always necessary, especially in smaller flow rate systems when adequate pre-filtration and sub-micron carbon block filters are used.
Activated carbon will break the chloramine bond and remove the chlorine component leaving free ammonia (NH3+). RO membranes are transparent to dissolved gases that will pass freely through the membrane concentrating in the RO product water.

Generally, reverse osmosis water is slightly acidic, due to the higher ratio of free CO2 to bicarbonate alkalinity. The exception to this rule is the presence of high pH “soda-lime softening” used by some municipalities. Free CO2 dissolved in water forms carbonic acid that lowers the pH to the range of 5 to 6 pH. In low pH RO product water, the ammonia is converted to the ionized ammonium ion NH4+. Downstream de-ionizing resins can then easily remove this charged species. It is cationic and removed by strong acid cation resins (in the hydrogen form) in either mixed bed or separate bed systems. Aquarists can be certain that when salt is properly added to RO or RO/DI water, the expected salinity and pH will be realized.