[67cruiser]

Testing my ph tester in 4.0 Buffer solution and its jumping around all over the place from 3.3 to 4.7. Never staying put.Does buffer solutions go bad?? Mine is 3 yrs old.

[fiedlerh]

Buffer solution should be replaced every year. I have used 3 year old solution without problems though. pH probes do go bad after a while for various reasons. Try leaving the probe in water or the buffer overnight and see if it settles down. Is this a battery-powered instrument? Stray voltage can make readings jump around, but this is more common with externally powered units.

[67cruiser]

Thank You very much for that input, i just removed my probe after 3 hrs. from the 4.0 Buffer and doing same thing. Ill try overnite.Are the probes replacable or not worth it??

[fiedlerh]

pH probes only last 18 months to 2 years. Shorter if they get contaminated, coated with gunk, or left to dry out. It's normal to replace them when they won't calibrate anymore.

Readings jumping around is often a sign of electrical interference. pH is a very low level signal and will pick up anything if the wiring isn't well shielded. If it's a hand held instrument and using it in a different location makes no difference, then I would suspect a bad probe or possibly a problem with the instrument.

[67cruiser]

ok, i can,t find any info on probes, how do you change them????

[fiedlerh]

I've had good luck googling the model name & number and finding the instruction manual.

Some very inexpensive hand-held units with the probe built into the housing are throwaway products.

[67cruiser]

I paid 30.00$ for mine and afraid thats what i have to. soaked overnite in 7.0 buffer and still doing same thing, Time to say good bye to it!!