How to clean pH probes?

[sid700]

Do I soak this in vinegar? tia

 

[Gomer]

Should work fine. Vinegar has a pH of ~2.4. I've seen instructions using solutions as strong as pH of 1.

 

[dswong01]

Tony
How much time will a probe typically last? will cleaning prolong?

 

[Gomer]

I'm no authority on them, but...

short answer: potentially many many many years if treated properly. cleaning is important for their longevity.

Long answer (with a fair bit of rambling):
IME, pH probes can last many many years. Of course, this is from a lab setting (taught a few analytical labs) where there is no budget....so they aren't replaced till broken In that setting, probes were binary. They either catistrophically failed, or worked. When they worked, as long as they were cleaned, calibrated, and stored properly, they worked perfectly. I recognized many of the probes as being many many years old.

On the cleaning side, it is probably good to know how (superficially) a pH probe works first. A pH probe has a glass section which you expose to something (in our case, tank water). This glass IS the critical part. It is a very fragile, POROUS membane. Thats right, porous ...super tiny holes that ions can transport through Why do I tell you this? Because calcification can clog the pores. A dilute acid bath is what cleans this out. However, acid doesn't clean everything. Touching the glass with oily fingers, for example, can clog the pores and impair performance. Algae on the surface can do the same. The best bet is to not physically touch the glass if you can help it.

Acid helps break down some contaminates, and base others. We all have vinegar around and that works well. You can also use


Here is some good info

Cleaning & Electrode Storage

Make sure to store the electrode in its Wetting Cap containing Electrode Fill Solution. Electrode Fill Solution (3M KCl) can be purchased or made (dissolve 22.37 grams of potassium chloride into 100 mL of DI or distilled water). Do NOT store the electrode in deionized water.
Troubleshooting

1. Clean the electrode.

2. Place the meter into absolute mV mode.

3. Place the electrode into a pH 7 buffer. The mV reading should be 0 +/- 15 mV.

4. Rinse and place the electrode into a pH 4 buffer. The mV reading should be 159 to 186 mV more positive than mV value in pH 7.

5. Optionally, place the clean electrode into a pH 10 buffer. The mV reading should be -159 to -186 mV less than mV value in pH 7.

Cleaning Procedure
General:

1. Soak in 0.1M HCl for half an hour.
2. Drain and refill the reference solution.
3. Soak the electrode in filling solution for one hour.

Inorganic:

1. Soak in 0.1M tetrasodium EDTA solution for 15 minutes
2. Drain and refill the reference solution.
3. Soak the electrode in filling solution for one hour.

Protein:

1. Soak in 1% pepsin / 0.1M HCl for 15 minutes.
2. Drain and refill the reference solution.
3. Soak the electrode in filling solution for one hour.

Grease and Oil:

1. Rinse with detergent or ethanol solution.
2. Drain and refill the reference solution.
3. Soak the electrode in filling solution for one hour.