ACIII two ph probes question

[bcjm]

I replaced the ORP probe with a second Ph probe in my AC III. I plan to use one to measure the calcium reactor ph and the other one to measure the tank water ph. After the calibrations of the first probe I put it into the sump, it shows ph 8.1. After the calibration of the second probe I put it into the sump also (about 2 ft apart between the probes), the reading of the first probe drops from 8.1 to 7.8 right away. It went back to 8.1 once I took the second probe out. Each probes seems to read correctly individually in the calibration solutions but not in the same water. Does it mean I can't use two probes in the same system at the same time?

 

Bob

Edited January 18, 2010 by bcjm

[Jon Lazar]

If you can't get an answer here I would email Curt at Neptune and ask him.

[flowerseller]

I'm assuming,

you can verify the functionality of each probe - new, known age, or source

you changed the second port from orp to pH.

you did the full calibration for each probe and verified together

you have your temp probe in the water at the time

[flowerseller]

my 2 pH probes are off by .02