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Thread: Testing CH levels in a pool with copper

  1. Back To Top    #1

    Join Date
    Jun 2008
    Location
    Tucson area, AZ
    Posts
    344

    Testing CH levels in a pool with copper

    Hi!

    Questions about testing CH levels in a pool with copper.

    I have decided to start shocking with cal-hypo, even though still using liquid chlorine for daily chlorination. The reasons behind this are a pulled muscle in my right side, the fact that my calcium hardness levels are low enough to be able to do this, and the heaviness and awkwardness of liquid chlorine. I tested my CH levels at 150 a little over a week ago with my TF100 test kit, BTW.

    Needless to say, I know that I need to be sure my test results are always correct when using a chlorine that adds calcium to the water. Leslie's had tested my CH at 250 only a week before I tested 150.

    My questions are this:

    1. In the instructions, it says while testing calcium to add 2 drops of R0012 prior to adding the R0011L if there is copper in the water. I know I have some, since I had put the PoolFrog BAM (a copper based algecide) in the water at the beginning of the season. So I did this. In Leslie's, they use Taylor reagents, and while I do not if the CH test works exactly the same, I do know that she did not put in a couple of drops of the one reagent, and then add the other; she just did the reagents in order. Could the difference in testing have made such a difference in the results?

    2. How much copper has to be in the water in order to have to add 2 drops of R0012 prior to adding the R0011L? 1PPM? .5PPM?

    3. In order to test my copper for the purposes of this test, should I get a copper test kit, or is the aqua check or some other guess strips sufficient to give me an idea? I'm just wondering how accurate I have to be in finding out how much copper I have in my water. At Leslie's they tested .15 ppm, but I'm not sure how much I trust that, because the manager was trying to tell the girl doing the testing I "didn't need" my copper tested, and "don't waste chemicals." I managed to talk them into it, but with an attitude like that, who knows how long that reagent was sitting around!
    Above ground soft side Omega pool
    20 feet diameter, 4 feet deep
    Hayward sand filter
    Hayward 1 HP Matrix pump
    Hayward Aquabug Automatic Pool Cleaner

  2. Back To Top    #2

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,085

    Re: Testing CH levels in a pool with copper

    The only issue with metals in the water such as copper and the CH test is that you can get a fading endpoint that is not distinct. That is, you add drops and get to a point where you see a color change, but then it goes away fairly quickly so you add more and it goes away, etc. or the endpoint looks more purple than blue. Adding drops of titrant initially binds up the metals to prevent this. As for how much to add, it's whatever amount it takes to prevent the fading endpoint so use the stability of the color transition as your guide for that. Also, read waterbear's posts about the CH tests and thoroughly mixing after each drop of titrant -- he waits up to 30 seconds between each drop if manually stirring -- using a magnetic stirrer lets you go quite a bit faster. This is not a fast test if done properly. See this link from Taylor for more info.

    Richard
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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