pH and ORP readings way off

[Armando]

I just got a new Aquacontroller II from Marine Depot, the deluxe package.

After everything is installed, I am getting pH and ORP readings way off. The pH is 5.8 and the ORP is 175.

I tried to calibrate the pH probe but nothing changed. I also tried to temporarily unplug the serial cable (as described in the troubleshooting section of the manual) but didn't fix the problem.

What should I do?

 

[kattner]

ORP will take several days to stabilize with a new probe. As to pH, did you calibrate with the pH 7.0 and 10.0 calibration fluids?

 

[Armando]

yes i did, after i placed the probe in 7, the display showed 5.30 and after i stepped forward in the setup process and placed the probe in 10, the displayed showed 5.29. Is that normal?

 

[kattner]

Sounds like you are missing a step, but I can't tell for sure. After you let the probe settle in the pH 7.0 fluid, you have to let it sit for a while until it quits changing - about 5 or ten minutes, then hit the set button for it to calibrate at 7.0. Then step on over to the setup for pH 10 and let it sit 5 or ten minutes there until it quits changing, then hit the set button. The display should say "updating" or something like that. After all that then get out of setup and go to the 'run' display and see if it is working.

If not, then

turn off the AQII and unplug the battery and let it sit about a minute, then put back in the battery and power up. You won't lose any programming, but will have to reenter the time. Then try and recalibrate. I had this problem once and Curt at Neptune systems told me that the power down will reset the unit and allow the internal memory to be updated with the pH calibration settings. If this doesn't work, call Curt at Neptune, he is very helpful.

 

[Armando]

just tried that. same results. very frustrating.

 

[clp]

Any chance the rubber cap is still on the pH and/or ORP probe? What reading do you get if you plug the pH probe into the ORP connector?

Curt

 

[Armando]

OK so I switched them up, now I have the red probe on the ORP connector and the blue probe on the pH connector.

The pH now reads 8.2 so I think it's correct.

But the ORP reads 120. Why would that be?

 

[clp]

There is a break in period for the ORP probe. Typically, they read between 100 and 200 when first installed, and then the ORP increases by 25 to 50 mV/day until it stabilizes. This break-in can take as long as 1 week.

Curt

 

[Armando]

sounds great. it's already in the 140 range.

Thanx!