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Thread: Prime and Ammonia - the False Positive Myth

  1. #1
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    Default Prime and Ammonia - the False Positive Myth

    There is some confusion about this. If you are using the API test kit, there is no false positive. The API test for ammonia tests for TOTAL ammonia, or the sum of toxic NH3 and relatively non-toxic NH4. So the test doesn't tell you anything about how toxic the ammonia is, whether the toxicity is due to the effect of pH on the NH3/NH4 equilibrium, or due to Prime having bound it to the NH4 form. This is true for any salicylate test, the kind that goes from yellow to green.

    -- If you take water that contains no ammonia, add Prime and test it, the test will still show no ammonia.

    -- If you test tank water that contains ammonia, you will get the same test result whether it has Prime added or not.

    -- If you test tap water that has chloramine, the test will show some ammonia. Adding Prime will break the chloramine into its parts, and detoxify the ammonia. Now if you test it the test will still show the same amount of ammonia it showed before adding the Prime.

    The test is always doing exactly what it is intended to do, which is measure total ammonia without telling you how toxic it is.

    Here are a few statements from Seachem tech support:

    With most kits which test for total ammonia, (like the API test kit) you will get an accurate total ammonia reading but not an accurate free (toxic) ammonia reading. What this means is that it will not tell you if the ammonia has be detoxified.
    https://www.seachem.com/support/foru...alse-positives

    You are correct in your statement that our previous posts are stating that this false positive is not the result of an indication of ammonia when there is not any present. The test kit is not giving a false positive due to the components in Prime.
    https://www.seachem.com/support/foru...monia-readings

    I don't know why they even use the words "false positive" in any of this. I suppose that if you were expecting the Prime to make the ammonia disappear from the test, then you might think of it as false. But there is nothing false about it since the ammonia is still there, although in a non-toxic form.

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    James Walker

    Default Re: Prime and Ammonia - the False Positive Myth

    Bottle one of the ammonia API test kits contains NaOH and NaOCl. This will convert both ammonia and ammonium to chloramine. Chloramine is what reacts with salicylate to generate the color.

    Prime/Safe is some sort of sulfite salt, it's function is to react with chlorine (NaOCl), chloramine, and ammonia. While it might not give a false positive, it is difficult to imagine an accurate test when you are adding introducing a reagent (Prime) the function of which is to react with three of the 4 or 5 components of the test kit.

    It might not give a false positive but it is difficult to see how it couldn't potentially have an impact on the accuracy of the test, especially when it is employed at high levels to prevent harm to fish.

  3. #3
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    Default Re: Prime and Ammonia - the False Positive Myth

    You can easily verify it yourself. Just take some water, with or without ammonia, and test it before and after adding Prime to see if the Prime has made any difference in the color. I think you will find, as I have, that it doesn't make any noticeable difference.

    It was a few years ago when I tested it. I think I used a triple dose of Prime and still couldn't see any change. It would be great if some forum members who are curious did the before-&-after test. It only takes a few minutes.

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