PH Probe, When to Replace

[Unexpected]

How often to completely replace your pH probe?

Thank you for any input.

I went over a year with my last one and boy was it nowhere near my new one. Even after calibration.

 

[Art]

@Unexpected I don't think there is a rule of thumb for this. You change it when it no longer holds a calibration.

My process is to test the probe monthly using the 4 and 7 pH packets. If it's off, I calibrate it. If it needs calibrating every month or sooner, it's time for me to replace.

Hope that helps.

 

[rzn7z7]

@Unexpected I don't think there is a rule of thumb for this. You change it when it no longer holds a calibration.

My process is to test the probe monthly using the 4 and 7 pH packets. If it's off, I calibrate it. If it needs calibrating every month or sooner, it's time for me to replace.

Hope that helps.

I'll second that....while I don't calibrate monthly I've found that when, during calibration, the pH probe can't settle/stabilize on one of the calibration values after 10-20 seconds and, instead, continues to bounce around that that's an indication the probe has reached its end and should be replaced

 

[Unexpected]

Thank you both!

 

[GreggZ]

Much depends on the probe itself. Cheap probes don't keep calibration very well, and need to be replaced more often. This goes double for the cheap pH pens that are widely available. Most don't last long and you end replacing them on a regular basis.

When you go to a good quality double-junction probe they can last many years and they keep calibration very well.

My last American Pinpoint Marine lasted almost 5 years. My latest one has about 3 years on it. I calibrate once a month and it's rarely off more than 0.05. Buy good quality up front and you get years of trouble free service.