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Thread: High Potassium levels after charcoal filter.

  1. #1
    Join Date
    May 2015
    Location
    Salem, MA, USA
    Posts
    16

    High Potassium levels after charcoal filter.

    Hi There,

    So we are on the cusp of opening and i sent 2 water samples to ward labs. 1 bottle of city water before it hits our 6 foot tall, 2 foot wide Charcoal bed, and 1 bottle after it had been filtered. We used 6 Cu Feet(165 pounds) of Bulk Coconut Carbon Drinking water grade 12X30 on top of 150ish pounds of Peastone in the filter.
    Unfiltered Sample
    pH 7.5
    TDS 396
    NA 98
    K 3
    CA 17
    Mg 6
    Total Hardness 68
    Sulfate 5
    Chloride 159
    CO3 <1.0
    HCO3 41
    CaCO3 34
    P 0.02

    Filtered Sample
    pH 9.4
    TDS 542
    NA 88
    K 112
    CA 9
    Mg 4
    Total Hardness 39
    Sulfate 4
    Chloride 146
    CO3 20.1
    HCO3 152
    CaCO3 153
    P 2.64

    As you can see the changes between the 2 samples there are some expected loss and then some very unexpected increase in K, Cl and Bicarb. I called Ward Labs and he believes something may of been infected with K leading to the increased levels of K carb and K bi-carb. Im trying to hunt down what it could be but i was looking for some input on where to look. It seems like it should really only be from the Carbon or from the Peastone. We rinsed the Peastone of as much residual much and dirt on it. The carbon is still relatively new, with only a few hundred gallons run through it. Will the K levels come down with time as we continue to use the filter, or did we end up with a product that is bad and we need to arrange replacement?

    Cheers,
    Jeff Marquis

  2. #2
    Join Date
    Oct 2002
    Location
    Chesterfield, UK
    Posts
    1,921
    I suggest it is the peastone that is dissolving. In the UK you can get peastone gravel from several different base stones, including limestone - perhaps in the states you limit the description to igneous rock only. Since your carbonate, bicarbonate and pH have gone up substantially, this suggests to me that the stone is either limestone based, or has a high level of limestone contamination.
    dick

  3. #3
    Join Date
    May 2015
    Location
    Salem, MA, USA
    Posts
    16
    Quote Originally Posted by dick murton View Post
    I suggest it is the peastone that is dissolving. In the UK you can get peastone gravel from several different base stones, including limestone - perhaps in the states you limit the description to igneous rock only. Since your carbonate, bicarbonate and pH have gone up substantially, this suggests to me that the stone is either limestone based, or has a high level of limestone contamination.
    Hi Dick,

    Id done some reading and it suggested Granite can have a large Potassium %. Do you think this is something that will leech out quickly or i need to refill the carbon bed?

    Cheers,
    Jeff

  4. #4
    Join Date
    Oct 2002
    Location
    Chesterfield, UK
    Posts
    1,921
    Why are you worried about potassium. As far as I am aware, it has no effects on beer - at least I have never seen anything mentioned, and certainly not at these levels. I would be more concerned by the increase in alkalinity and pH. I doubt very much of you have pure granite chips. T check if there is limestone in the chips, simply throw a few chippings in some dilute mineral acid - HCl, H2SO4, HNO3 will all work. If it fizzes at all you don't have pure granite chips, but have at least some limestone (with other entrained mineral impurities)
    dick

  5. #5
    Join Date
    Nov 2010
    Location
    Carmel, IN
    Posts
    50
    While malt contributes huge amounts of potassium and magnesium to wort, those malt derived components are different from those contributed by the water. I've heard of several brewers complaining about beer flavor after adding potassium salts. I would be cautious if the testing indicates that its spiking after the filter.

    I see the filter been flushed with many tank volumes of water, but have you conducted subsequent testing and testing on water samples that represent 'first flush' and well-flushed conditions?

    PS: I see that activated carbon is often treated with potassium hydroxide to aid in activating the carbon. Assuming that this filter is being used to dechlorinate the incoming water supply, the leaching of potassium may be a continuing issue since the dechlorination process consumes the carbon mass and that would likely expose new surfaces of the activated carbon to be exposed. If the potassium problem continues, carbon replacement may be needed.
    Last edited by WaterEng; 03-22-2019 at 05:39 PM.
    WaterEng
    Engineering Consultant

  6. #6
    Join Date
    Oct 2002
    Location
    Chesterfield, UK
    Posts
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    Interesting comment about potassium salts affecting flavours. BUT, are you (or more correctly, the brewers who perceived these flavour changes / problems) sure that the flavours are due to the potassium, and not the chloride or sulphate forming part of the potassium salts added?
    dick

  7. #7
    Join Date
    May 2019
    Location
    New York
    Posts
    1

    Is that true?

    Really? Is that true?

    Please ellaborate. Can we solve this? How?

    Can
    watersoftener do something?

  8. #8
    Join Date
    Oct 2002
    Location
    Chesterfield, UK
    Posts
    1,921
    Is what true?

    I am not clear what you are asking to be clarified
    dick

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