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Thread: New pool store water testing equipment / Chlorination question

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    BobbyR's Avatar
    Join Date
    Jun 2013
    Toronto, Ont

    New pool store water testing equipment / Chlorination question

    A few days ago I made my regular run to the local pool store to re-stock on liquid chlorine and took along a water sample for testing. I don't usually do that because I have the proper test kit but I thought I'd see how their results compare to mine. I discovered that they have a new system that was just installed that I've never seen before, replacing the usual equipment. With this new system they use a syringe to inject water into a disposable plastic disk like a small hockey puck which then is inserted into a machine which does the tests. After a minute the results print out. The system tests for everything including CYA. The results were pretty much identical to mine and, for the first time ever at a pool store, I wasn't advised to shock my pool and/or to adjust my ph and TA. The results were all ok with no recommended intervention. Will wonders never cease?

    Has anyone else encountered this system? It seems to be less error prone because it's so automated and isn't so subject to carelessness and contamination as the old manual equipment with its beakers, titration tubes and whatnot.

    Also, I seem to go through more chlorine than I expected to. My pool is in full sun for much of the day so I have the CYA at 50ppm but I find it really difficult to keep the level at the recommend 6ppm. I chlorinate in the evening and by then my TC has usually dropped to near zero which I know is not good. I have no overnight chlorine loss and my water is clear so I don't think there's anything growing in my pool. Should I be adding chlorine more often in smaller amounts to maintain the level? That would be more difficult as I'm not always home during the day. Raising the level to 6ppm from near zero ppm every day is consuming a lot of chlorine, almost 4 litres a day of 11% liquid chlorine. What should my 24 hour loss be if everything is working properly? I thought it would only drop to 3 or 4ppm between applications but that's not the case. Am I doing something wrong? Also, my pH tends to creep up despite adding acid to bring it down. Will it eventually stabilize?

    This morning's readings:

    FC - 6
    CC - 0
    TA - 100
    ph - 8
    CYA - 50

    Water is clear and clean except for overnight worms from the rain.
    Lagoon 40x22, Vinyl, 27,000 gal, 1HP WhisperFlo Pump, Pentair 60 gpm Sand filter, Hayward Brominator (used for chlorine pucks only when away), Rheem gas heater, Dolphin M4 Robot
    Waterfall on separate dedicated pump

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    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Franklin, NC

    Re: New pool store water testing equipment / Chlorination question

    A couple of stores near me have had that for over a year. It seems ot be a product from LaMotte, the WaterLinkŪ Spin Lab. I don't know if it's calibration, maintenance or what, but the ones I have seen can be very close to my testing (like you experienced) or way off. And that is the same machine in the same store.

    Stick with the Taylor drop based testing to care for your water. Your pool will thank you.
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  3. Back To Top    #3

    Join Date
    Aug 2014
    Shallotte, NC

    Re: New pool store water testing equipment / Chlorination question

    I think the key, here, is CALIBRATION.... or, perhaps, the lack thereof. Without knowing whether the machine is actually checked frequently against a standard, it is just a bit more high-tech mumbo jumbo. Stick to *your* testing.

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