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serpentman
10/12/2009, 04:54 PM
I am getting really weird ORP values on my AC3. My Pinpoint is telling me I am between 370-410mv.2-5. However, my AC3 is saying 18-30mv.2-5. Something isn't right. Hope the Pinpoint is correct.

I know the value itself isn't as critical however, the disparity is concerning as I don't know which unit to trust. Could the margin of error be that much between the 2?

bertoni
10/12/2009, 05:45 PM
It sounds as if the AC3 is having some problems. Maybe the probe is in a bad area in terms of electrical or water flow issues? Has either been calibrated?

serpentman
10/12/2009, 06:58 PM
Yeah, both meters are calibrated. I have tried moving the probes as well figuring it was stray voltage. Very strange...

bertoni
10/12/2009, 10:13 PM
18-30 mV isn't credible. I suspect there's something wrong with the AC3.

tgray3
10/12/2009, 10:20 PM
My Hanna probe read between 18 and 37mv when it was new. I soaked it in Hanna storage solution for 12 hours then cleaned and re-calibrated it. After that is hasn't given me any trouble.

Randy Holmes-Farley
10/13/2009, 04:52 AM
Yeah, both meters are calibrated.

If you put both probes in the same calbration solution, they read the same?

serpentman
10/13/2009, 05:49 AM
Actually, I didn't think of that. The AC3 uses quin-7 and quin-4 solutions. The pinpoint uses an ORP standard. However the AC3 should give me the same reading when placed in the standard.

Randy Holmes-Farley
10/13/2009, 06:16 AM
Yes, put both probes in any of them. Maybe one of the standards is off.

serpentman
10/14/2009, 04:19 PM
After speaking with Neptune, I believe the issue is with my calibration. I misunderstood the procedure. They call for the addition of quinhydrone to the 4 & 7 standards. Can anyone advise as to where one might find this?

bertoni
10/14/2009, 05:24 PM
I only found it easily on the Marine Depot web site, but others might stock it. Googling 'quinhydrone powder' found a vendor or two, but I have no experience with them.