pH meter repair/clean.

My pH meter (pen-type, cheap £10 job) stopped working after a winter of being unused. Tried soaking the probes in distilled water but no use. A couple of hours in distilled white vinegar have bought it back to life though! Hope someone finds this useful.

I’ve always heard distilled water is no bueno for ph pens idk. A couple drops of solution a month is cheap and easy enough

What solution are you using?

cues said:

What solution are you using?

Click to expand...

The vinegar probably dissoved the calcium deposits on the probe, got it working for you.
The KCI is storage solution

Method 1
Soak the electrode in a 0.4 molar concentration of HCl (hydrochloric acid) for 10 minutes, then rinse the electrode with deionized or distilled water. This should remove any organic protein from the glass electrode and the surface of the reference electrode.


Method 2
Soak the electrode in a 3.8 or 4.0 molar KCl (potassium chloride) solution heated to 50°C for 1 hour. Allow the KCl solution to cool down to room temperature, then rinse the electrode with deionized or distilled water. This will open and clean the reference electrode of all contaminants.


Method 3
Soak the electrode in a 4.01 pH buffer solution , heated to 50°C for 1 hour. Allow the buffer to cool down to room temperature, then rinse the electrode with deionized or distilled water. This will open and clean the reference electrode.


Method 4
For protein removal, soak the pH electrode in contact lens enzymatic cleaner solution overnight. The enzymes will remove proteins from glass and plastic.

Storage
Note: never store your PH electrode in distilled water.

Bluelab uses 4M KCI, Apera uses 3M KCI, others use 1M KCI solution, proper chemical makes it read faster, more accurately and extends service life.
It is also possible to use pH 4 reference solution, if you don't have KCI for storage

This is what they had last time but it doesn’t matter

Nice. My bad I guess. Jut happen to have a distiller and was the first thing that sprang to mind. Got a couple to restore before the season kicks in so the pH 4 reference solution is handy to know. Intended to knock some up anyway. TBH i miss the old drip kits but they're impractical now with 4 reservoirs to monitor.

On the package it says you can soak the prob in ph 4 buffer so I'm assuming the vinegar did the same thing. Cheap meters are ... Well.... Cheap and inaccurate. Check out the Hanna phep series. It's only about 70-100$ and prob the best pocket pen style ive ever used with replacement probes available

this ones been working like a champ last couple years. amazon.
only time ive had to calibrate was after the batteries got weak and I futzed with it before realizing it was the batteries.
rinse with clean water, shake off excess, cap it.
I look for a detachable probe and one that can be immersed for as long as you want.
inexpensive isnt always cheap.