Redox / ORP Probe

[balloonpilot]

Im having troubles with my Redox (ORP) Probe.

First, I must say that NEITHER of these probes are GHL probes. The 'old' one is the yellow one sold by Bulk Reef Supply and the 'new' one is the red one used on Neptune (I have these because I could not get my hands on the GHL Probes.

Here are my readings comparing the 'old' probe along with the 'new' probe:

Old Probe in Measurement Cell 202
New Probe in Measurement Cell 152

Old Probe in Sump 196
New Probe in Sump 148

Old Probe in 220-270 Test Solution 243
New Probe in 220-270 Test Solution 232


So both probes 'calibrate' within reason and there seems to only be 4 to 6 points difference if testing IN or OUT of the Measurement Cell

The Old probe, after taking it out of the Test Solution and placing it back in the Measurement Cell starts out reading 167 (close to what the new probe reads) however the reading from the old probe then start to climb and stabalize around the 195 range

Question - IF both probes calibrate closely -- Why do they NOT read the same once inserted into the Measurement Cell ? I can live with +/- 10 or so, but 50 seems like way too much of a swing. Plus, why would the 'old' cell take time to climb up until its 50 higher ?


Thanks

[Vinny]

I cannot comment on the accuracy/sensitivity of other brand probes as each probe may have been made to different standards right out of the factory.

We have Redox probes in-stock at our warehouse. These can be found in our USA online store:
https://www.aquariumcomputer.com/usa...dox-electrode/