Argh, darn you, pH probe!

So it looks like my pH probe might have taken a crap. First time I've had a digital meter, and, to be quite honest, I've taken shit care of it. Hardly cleaned it, haven't calibrated it since I bought it (which was 1.5yrs ago..), and it's probably been accidently left out to dry a few times. I'm surprised it hadn't failed sooner.

Anyway, I have a Bluelab Combo Meter, and I just purchased calibration solution and cleaning solution from the store. I cleaned the probe thoroughly just as suggested in the manual and the cleaning solution (also tried dish soap later). Calibrated it with 7.0 solution, and then when I went to go calibrate it for 4.0, I received the error message "E2H."

I looked up the error message in the manual, and this is what it said:

E 2 : PH

pH10.0 calibration solution contaminated or wrong solution used. Probe contaminated, not properly attached, worn out or damaged.

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So, now I'm slightly worried. My local shop has to special order these things, and I don't exactly have enough dough on hand to pick up a new probe anyway.

Does anybody have one of these units, and have they run into this issue before? Were you able to fix it? Also, can you use a non-Bluelab pH probe with this combo meter as long as it has a BNC connection?

I'll pick up some pH papers later this week, but that's about the best I can do for a while.

Kind of a shitty position when you've got an aero cloner with a bad root rot issue on the side..

Soak the probe in storage solution for a few hours, then try again. No storage solution: try pH 4.01 buffer for a few hours.

Also check: if it's a refillable electrode, make certain the solution hasn't leaked out or evaporated.

Last ditch: before throwing it out, soak the probe in dilute hydrochloric acid (we use 0.1 molar in the lab). Vinegar might work in your situation; dunno.

Thanks for the response. I soaked it overnight in storage solution, no change. Trying pH 4.01 buffer solution now.

It's not a refillable electrode, but that doesn't necessarily mean the gel hasn't leaked out. Would it be in the large outer vial, or the small inner vial? It's hard to tell if there's liquid in either of them.

Here are some pictures for reference..









Any and all help is appreciated, and rep'd accordingly.

To answer your previous question, you can use any pH probe, provided the connector is correct. There are also adapters, but it's easiest to just get the right kind to begin with.

Out of curiosity, if you try to measure the pH 4.01 standard, does it at least read it accurately, even if it won't calibrate?

For reconditioning, in order:

4.01 buffer solution for several hours.

HOT 4.01 buffer solution.

Physically wipe the bulb (which is very easy to break) with a cloth.

Lastly: soak in 0.1 molar hydrochloric acid (vinegar might work- I dunno) for an hour. Wash. Soak in 10% bleach solution with a tiny amount of detergent, heated to about 50C. Swirl for 15 minutes. Then soak in saturated potassium chloride at 50C for an hour. Allow to cool to room temperature, rinse once with clean water. If you don't have access to KCl, then you might try Morton Lite Salt. I heard one of the salt substitutes is pure KCl, but I haven't read enough labels to find it in the stores. I think pickling salt may be potassium chloride, too, I dunno.

Anyway- those are the things to try, in increasing order of difficulty.

if you have no means of gettin a meter working and you had to, i suggest you try ph drops instead of paper, i have worked with drops for years, and the best i have used were the Sera brand

YThor said:

Out of curiosity, if you try to measure the pH 4.01 standard, does it at least read it accurately, even if it won't calibrate?

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No, it reads 6.7-6.9 when placed in pH 4.01 buffer solution. However, I'm soaking it in hot 4.01 buffer solution now, and I have gotten a few more accurate readings. Since I started soaking it, which was about ten minutes ago, it has started to decrease. It currently reads 6.0, which might be a good thing? We'll see. I'm hopeful, as I haven't seen a reading below 6.5 since before I started having these problems.

I'll report back later on. Thanks again.

Update: After 20-30 minutes, when placed in hot 4.01 buffer solution, it will read 4.2-4.4, but that number quickly climbs when it is taken out of the heat. I will let it sit for a few hours, and hopefully it will stay put.

i suggest you buy a new metre and look after it, the price of a new electrode can be half the price of a new meter and its not guaranteed to work, the problem may not be the electrode, i wasted loads of money trying to fix the unfixable.

take it back, they have a 5 year warranty

caddyluck said:

take it back, they have a 5 year warranty

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Yeah, this is driving me nuts. Tried every reconditioning method except the one with HCl/KCl (not exactly stuff everybody has easy access to), and it doesn't really seem to have made much of a difference in the long run.

I don't think it's the meter, since I take good care of it. It's just the probe that I didn't look after. I'm throwing in the towel and picking up a replacement:

http://www.amazon.com/American-Marine-Pinpoint-pH-Probe/dp/B001EHJO64

End result, new probe fixed the problem. Everything calibrates properly and I get accurate readings. Thanks for the help, guys.