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Thread: Is my PH probe dead?

  1. #1
    tom Guest

    Default Is my PH probe dead?

    I have a older Hanna grocheck combo (such as ) which I bought in 2006 or 2007. I used it for months and when done, stored it as per the instructions (in 7.0 solution).

    I used it again recently in late 2009 and it worked great. But I stored it for only a month or so in RO water by mistake. Now, when I tried to calibrate it, the 7.0 calibration seems to work fine, but I cant get it to read the 4.0 buffer solution at all. It'll read maybe 5.5 to start, then drift upwards over 6.0.

    I've searched online and found several sources of information suggesting to heat up some 4.0 buffer solution and let the probe sit in it for a while to reactivate the glass. I've tried this twice now, and with heated 4.0 solution it'll read as low as 2.5 or so initially, but AGAIN it always drifts back up over 6.0. I even had a brand new bottle of solution stored and opened it and tried it. Same thing.

    I have scrubbed the glass probe tip carefully with solutions and with plain RO water. Tried and retried the warm solution.. soaked it over night for many nights, and finally I'm trying to post on the forum here for some expert advice.

    I realize that there is a cleaning product made for it which I have not tried yet, I also realize that these probes are known to be finicky and only guaranteed for 6 months and I should count my blessings. I also know that some people foolishly submerge the entire probe which I have not ever done. I've used it properly with the single exception of accidentally storing it in RO water for about 30 days max.

    Is my probe dead finally? Should I spend 60 bucks or whatever it is for a new PH probe? Or maybe get a new meter entirely for slightly more?

    Thanks for any advice,

  2. #2
    Tom Guest


    Anyone? Anyone?

    I found my blue labs probe cleaning kit which consists of basically Soft Scrub and a small plastic tool to apply it. It didnt work. I guess I dont need an answer, it's pretty clear that the portion of my probe that handles the low end of ph is broken and I need a new probe. And hey, if it turns out that I dont, I'll just ask for a refund.

  3. #3
    Join Date
    May 2010


    it seems to me that your probe is a goner. however there is one last trick inthe book to try. soak your probe in 7.01 buffer solution for 24 hrs, then attempt to calibrate it again. i have used this method to varying degrees of success, but it's worth a shot before you spend the dough on a new probe.

  4. #4
    Tom Guest


    Hi David,

    Yeah I've had it sitting in 7 for weeks now it seems and it still is a goner on the low side. I'll probably order a new probe for it unless I find a nice handheld at half price or something. Thanks

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