ORP probe malfunction?

[szwab]

I picked up some calibration fluid for my probe. The other night my orp was at 350. The calibration fluid was 250. I wanted to check the probe (mostly curiosity). The probe read around 212 in the fluid. I rinsed it off real well and put it back in the tank. It did not go back up to 350, which I presumed it would. Today when I checked it was up to 280. Did I break it? Or will it just take a bit for it to go back up? The probe is only about 3 months old.

 

[clp]

Most likely there was a biofilm on the tip of the probe, and that resulted in the higher 350 reading. When you rinsed the probe you removed the biofilm, and the reading went back to the correct reading. When moving the ORP probe from very different solutions it may take a few hours for the reading to stabilize.

Curt

 

[szwab]

thanks for the quick response. I guess the one nice thing is they read high instead of low