Chloramine VS. DI Resin In Your RO/DI Filter

Discussion in 'Water Chemistry' started by Matt Rogers, Oct 16, 2009.

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  1. Matt Rogers

    Matt Rogers Kingfish Staff Member

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    Chloramine has been added to a lot of our tap water as a water disinfectant. Some of you may know that a lot of chloramine can kill your fish by reducing their oxygen in their blood. (Chloramine in the aquarium water can be broken down with poly filters, carbon and some water conditioners.) Some may even be concerned about the chloramine affects on humans. However, did you know that chloramine can rapidly deplete the resin in your DI filter and affect membranes? Neither did this 3reefer until an interesting discussion with Pete Brizio, the technical advisor at Aqua Engineering & Equipment, Inc..

    [​IMG]
    The Chloramine Compound


    Walking the aisles of MACNA recently, I was looking at a large Aqua FX reverse osmosis filter and noted some canisters on it I hadn't seen before. The gentleman behind the counter (Pete Brizio) explained to me that those were NH[SUB]2[/SUB]CL 'Blasters' designed to remove Chloramine.

    [​IMG]
    The NH[SUB]2[/SUB]CL Blaster Kit from Aqua FX

    After an explanation of how chloramine rapidly depletes the number of hours your DI resin will last I was facinated and that conversation has haunted me a bit since as I have not seen this issue addressed elsewhere or even really discussed. So recently I followed up with Pete and asked if I could get a bit more on the chloramine issue for 3reef. What follows is a letter from Marianne Brizio, President of Aqua Engineering & Equipment, Inc..


    More on the NH[SUB]2[/SUB]CL Blaster Kit from Aqua FX for your RO/DI filter

    Thanks to Pete and Marianne for bringing awareness to this issue!


    Aqua Engineering & Equipment, Inc. Web site:
    http://www.aquaee.com/

    The NH[SUB]2[/SUB]CL Blaster and other Aqua FX filters may be found here:
    http://www.aquariumwaterfilters.com/


    I find it interesting that this was determined by customers calling in after noticing that their DI resins were be exhausted. Have any of you noticed the same? Is there Chloramine in your water now? Have you developed any methods to deal with it? If so, please post!!


    matt
     
    Last edited: Oct 16, 2009
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  3. ZachB

    ZachB Giant Squid

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    Yea, I've had some issues with my local water. It's bad. It comes out of my tap smelling like chlorine mixed with mold. I refuse to drink it unless it's come out of my RO unit (DI bypass) In less than 6 months and probably less than 1,000 gallons my DI has been exhausted and I'm getting around 35 TDS out of my membrane. Both need replaced :angry:

    This looks interesting.
     
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  4. Dingo

    Dingo Giant Squid

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    this post reminds me of organic chemistry class... ughhhhh
     
  5. Biggs2003

    Biggs2003 Flamingo Tongue

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    interesting...
    I just had this same problem when I moved into the city last month. I called the manufacturer of my RODI unit and was assured that the two GAC pre-filters would catch both chlorine and chloramine with nothing coming out of them to damage the membrane or DI resin. I haven't made much water since I've been living here (maybe 200 gal), but my TDS are still 0 coming out of the di resin.

    Here's the link I was given from the manufacturer as an explanation of it's ability to remove both chlorine compounds.

    http://59.124.16.10/items/PW-Pic/about_ro.jpg
     
  6. ZachB

    ZachB Giant Squid

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    I recently replaced the prefilter and carbon block on my unit. I'm seriously contemplating buying one of these, as a just in case type of deal. I don't want to have to keep replacing my membrane and DI every 6 months.
     
  7. ardo_ski

    ardo_ski Peppermint Shrimp

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    I surprised this is new to everyone. The Filter Guys set me up about 1.5 years ago. They also sell a simple test kit so you can test for Chloramine!
     
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  9. Jason McKenzie

    Jason McKenzie Super Moderator Staff Member

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    Wow Very cool read. Now I'm wondering if I need to go this way

    Very interested in this add on unit anyone have one?

    J
     
  10. AZDesertRat

    AZDesertRat Giant Squid

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    Everything you need for chloramines is right here:
    SpectraPure Customer Appreciation SALE! 20% - 50% off

    Too many vendors concentrate on the carbon when the DI is by far the most important part. A single high quality carbon block like the 0.5 micron in the above flyer is more than sufficient for chloramines at normal household levels below 2 mg/L and their DI resin cannot be beat by any one. I use the MaxCap followed by a SilicaBuster and its amazing.

    Low end systems rely on multiple carbons as they use low quality, low capacity carbon since it costs less and improves their profit margin. Often granular products are completely exhausted in as little as 300 total gallons, thats 60 good RO/DI gallons and 240 waste gallons at the normal 4:1 waste ratio. Compare that to a single 0.5 micron 20,000 gallon carbon block at 4,000 good and 16,000 waste gallons. Big difference.
     
  11. SpectraPure

    SpectraPure 3reef Sponsor

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    Fwiw- When it comes to chloramines-
    I really like data to determine carbon filter status-

    CHLORINE TEST KITS

    Also for additional background
    -
    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.

    Charles Mitsis
    President SpectraPure Inc.

    and...

    Probably the biggest environmental factor in removal of chloramine is the pH of the tap water. At a pH of 8.3, almost all of the chloramine is in the monochloramine form, which is much harder to remove. As the pH level is lowered, the ratio of dichloramines to monochloramines is increased. Dichloramine is very easy to remove by bituminous activated carbon.

    The combination of soda lime softening or sodium hydroxide (to prevent piping corrosion) with chloramines is the worst possible condition. The pH is then often in the 9 to 10 range and at that pH, chloramine is totally converted to monochloramine. The reverse osmosis membrane pores will swell by the combination of high pH and free ammonia. This causes very poor rejection of silica and phosphates, and passage of ammonia through the membrane. Hydroxide ions that are present are also very poorly rejected by the membrane so the pH of the RO product water will be high and ammonia laden, creating additional load to the downstream ion exchange resins.

    So, there are almost no universal solutions to water treatment. Environmental factors will weigh heavily in deciding how to best treat those individual water sources. I am working on new methods to treat chloramines and will soon have a new cartridge that will better treat most municipal water sources for chloramine removal.

    Charles Mitsis
    President SpectraPure Inc.


    bruce
     
  12. Matt Rogers

    Matt Rogers Kingfish Staff Member

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    Fantastic info. It's nice to have you around SpectraPure. I want to test my water now.
    (There are a couple scrambled words in there though - can you fix?)