lab grade vs. standard orp probe

dadonoflaw

New member
i want to use this probe to monitor my oxygen levels in a nitrate reactor. which probe would be suitable?
 

dadonoflaw

New member
yea thats what i want to do. i dont quite understand what curt is suggesting. should i have gotten a ph probe instead of an orp probe? or if i can use the orp probe what do i do to run it in ph mode?
 

clp

.Registered Member
Use an ORP probe on a pH connector to read negative ORP values. Of course the displayed units will be pH, but there is conversion information in the above referenced thread.

Curt
 

dadonoflaw

New member
ok i have an ac3 with an orp and ph probes. there is a slot for orp and for ph. if i plug the orp probe in to the ph connector is there anything i can do with the empty orp connector. can the ph probe plug into the orp connector so i know my tank ph?
 

kenargo

Premium Member
If you have an AC3 or AC3 Pro the probe inputs are configurable as either PH or ORP. It doesn't matter which probe you plug in as long as the pot input if correctly configured. If you want to monitor your reactor you can plug the probe from the reactor into the ORP probe connector and change the configuration to tell the AC3 that the probe is a PH probe; this will give you what you need to monitor the reactor.

Does this make sense?
 

dadonoflaw

New member
yes it does. thank you. is the info on how to tell the controller in the manual given or is there somewhere to find it? is it simple?
 

dadonoflaw

New member
ok i have the reactor up and running and i switched the orp probe to run in ph mode. i must have done something wrong as it red 48.5 and was climbing when i switched it back to orp. the orp reading is at 16 and dropping. i saw that it is supposed to read around 7.0 to measure negative values. what could be wrong? orp probe has been in water for a week.
 

clp

.Registered Member
It sounds like the pH calibration constants for pH2 are bogus. Put a pH probe on the ORP connector, and calibrate it. Then put the ORP probe and you should then be able to read negative ORP as a pH value as described in the other thread.

Curt
 

clp

.Registered Member
It depends on the ORP reading you are looking for. The translation to ORP will be about:

(7 - pH) * 58

So a pH of 11 is about (7-11)*58 = -232 mV.

Curt
 
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