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mrteam

Rapitest ph meter

mrteam
17 years ago

What is up with my Rapitest ph meter? I have searched the forum and seen that some people are happy with theirs and say it works well. Others, say it always reads close to 7.0 or neutral. Unfortunately, mine is in the last group. I know it is inexpensive, but it seems like it should give some indication if the soil is acid or alkaline. Could someone who is happy with theirs say what kind of readings they get and if their is a trick to it?

Comments (26)

  • bpgreen
    17 years ago

    I'm very happy with mine. Before I bought it, I thought I had very alkaline soil, especially in one corner of my yard.

    Now I know that all of my soil is pretty close to neutral, as it all tests at 7.

    Sorry. I couldn't resist. I don't really have one, but I was thinking of how happy I'd be if my soil had a pH around 7.

  • david52 Zone 6
    17 years ago

    I have the same results as bpgreen, surprisingly neutral soil. It also works as a decent moisture meter, in that if the soil is so hard I can't push it in, then I need to water.

    I, unfortunately, paid more for mine. I am not pleased with the product. I used pH meters often in my pre-gardening career, and I have yet to run across a meter were reliable results don't require frequent calibration with stock solutions, cleaning electrodes in solvents, and so on. Like the equipment they use if you send in a soil sample to a reputable lab.

  • Kimmsr
    17 years ago

    These relatively inexpensive pH meters seldom really work. To check yours test some vinegar and see what the pH is with that. Another problem with these pH meters is even if they did work you would not know why your soils pH was what it was or what to do to correct the problem.

  • keinley
    17 years ago

    bpgreen
    Man, that was awesome. I laughed pretty dang hard.

  • hilde_wny
    17 years ago

    That was really funny, bpgreen! :-)

  • jeannie7
    17 years ago

    For what they are used for and for what they cost, they can be the weedkend gardener's reliable friend.
    As most soil is indeed in the neutral range, there is no point in spending ultra dollars for something that wont be used for its importance.

  • nevada
    15 years ago

    I had the same experience until I discovered that it has an ON/OFF switch! When I set it to Ph, it showed 5. I had added sulphur twice and wondered why the Ph was always 7!! It's a good thing I discovered that switch before I added more sulphur!!!

  • gbmilo_aol_com
    13 years ago

    If you want to check out your pH meter to determine that it is working correctly do the following. no.1 of 3 no.1 Take some white vinegar and add a teaspoon to a smmall glass of water the pH should be circa 5.4 no.2 take some bicarbonate i.e baking soda and add a 1/4 of a teaspoon to a small glass of water . Be sure the bicarbonate is solubilzed. The pH reading should be circa 8.0 or higher. 3rd you can check the neutral pH of 7.0 by using a small glass of deionized water that has been under cap. The pH shoud be circa 7.0 Then check your soil for a pH reading.

  • ffreidl
    9 years ago

    Well, I have the same problem with my ph meter so I'm interested in anyone's fix. pbeemer's the only one who offered one - I'll try it out but not optimistic because mine is brand new (not likely to be already oxidized.

    Actually, nevada offered a fix too - I'll have to check and see if mine has an on-off switch. That certainly seems like the kind of thing that could be the problem!

  • ffreidl
    9 years ago

    What do you know? Pbeemer wins! I took a scrubby and scrubbed away, and now it's working! I didn't realize you had to scrub that hard and really try to take the layer off. I also didn't know you could use any plastic scrubby - I thought you had to special order the scrubby thing from the company.

    Thanks a million! Made my night!

  • Dustin Mask
    7 years ago

    I used a wire brush on mine the Brillo pad wasn't working the wire brush made it work.

  • toxcrusadr
    7 years ago

    Regarding the above 'calibration' tests with vinegar and baking soda: use distilled water for all of those. Tap water pH can be as high as 8, and if it is hard water, it can have a lot of carbonate and bicarbonate that will suck up acid and the pH will not be where it should be for vinegar. Any jug of distilled or deionized water will work.

    Actual soil measurement was not discussed in this thread but you should make a 50/50 slurry of soil and water (again distilled/deionized), let it sit for a few minutes and measure the liquid. Sticking the probe into the ground is not nearly as accurate because pH meters measure pH in a water solution, so measurements will be wacky if you don't have enough moisture present. Turns out diluting the soil with water will not affect the reading much as long as the amount of water is not huge compared to the soil, and as long as you use distilled/deionized water.

  • kimmq
    7 years ago

    You use this pH meter to test your soil and it tells you that your soils pH is x.x. How much of what do you need to add to make any corrections necessary?

    A good reliable soil test from a reputable soil testing lab will have that information.

    kimmq is kimmsr

  • Andrew X
    7 years ago

    I own a rapitest soil pH meter. I decided to try testing it with a solution of sodium bicarbonate also know as baking sofa. It should read basic but this meter reads acidic. Very strange. Also there is no on/off switch.

  • kimmq
    7 years ago

    Not at all strange, Andrew. I have seen that myself with several of those relatively cheap "soil pH" testers. They are very inaccurate and unreliable.

    kimmq is kimmsr

  • wayne_5 zone 6a Central Indiana
    7 years ago

    Mine showed the proper reading with the white vinegar and distilled water tests and I believe it is relatively accurate and of general use for ph readings.

  • Andrew X
    7 years ago

    It works ok in the acid range but it reads alkalinity as acidic as well. So as a pH meter it stinks.

  • wayne_5 zone 6a Central Indiana
    7 years ago

    Andrew, Are you talking about your experience or for all of them?

  • Andrew X
    7 years ago

    Well, I would like to hear what other people experience. Has anyone else tried testing the device using baking soda?

  • toxcrusadr
    7 years ago
    last modified: 7 years ago

    Andrew, how old is your device, and how long since it was last used? I assume this is a 'dry' probe not a water-filled one, can you post a pic or a link? If it is a wet probe it may need to soak in distilled water for a few hours, if it hasn't dried up completely inside which is even more complicated to fix. Is there any kind of adjustment on it? Does it have batteries and if so are they good?

  • Andrew X
    7 years ago

    These pH meters are for sale on Amazon where there is a complete description and photos.

    https://www.amazon.com/Luster-Leaf-1840-Rapitest-Meter/dp/B0000DI848

    Mine is about a year old.

  • toxcrusadr
    7 years ago

    If there is no on-off switch on this unit it is probably powered only by the voltage set up within the probe. I saw a pic of a simple one like that on the web.

    I assume you used distilled water with the baking soda?

    Does it read differently for distilled water vs. vinegar? What were those readings?

  • Andrew X
    7 years ago

    Vinegar pH 3. Water 7

  • toxcrusadr
    7 years ago

    I read the comments, in particular the large fraction of them under the "1 Star" rating. Interesting reading.

  • Andrew X
    7 years ago

    So?

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