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Rapitest ph meter

Posted by mrteam 8 (My Page) on
Thu, Feb 15, 07 at 19:06

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?


Follow-Up Postings:

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RE: Rapitest ph meter

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.


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RE: Rapitest ph meter

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.


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RE: Rapitest ph meter

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.


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RE: Rapitest ph meter

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


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RE: Rapitest ph meter

That was really funny, bpgreen! :-)


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RE: Rapitest ph meter

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.


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RE: Rapitest ph meter

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!!!


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RE: Rapitest ph meter

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.


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fixing your Rapitest ph meter

this is an easy fix.

over time a dark (oxide?) film forms on the tip electrode; this seems to passivate the surface and prevent the meter from working.

just take a PLASTIC scrubee (NOT a metal one!) and lightly scrub the lower electrode (which appears to be lead) until the dark layer is gone. the meter will again read pH.


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RE: Rapitest ph meter

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!


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RE: Rapitest ph meter

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!


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