Negative ORP with crossover cable?

[garbled]

Has anyone tried building a negative ORP probe with a bnc crossover, and hooking it to a neptune apex? Does it work correctly and display negative values as positive to the apex?

[kenargo]

It won't work but you can use a PH input as a way to get negative ORP; you need to search the threads for more details; the values will not read correct but hey will read and the threads have more detail. This is for use in a phosphate reactor?

[garbled]

It's for use in a sulfur reactor. If there is a simple calculation I can do, that works, as I pass most of my data through a math program to make graphs anyhow.

[kenargo]

Yup, I think that is what I ment, got my minerals flipped...

In any case; search the forum; there was some discussion back some time ago, maybe more than 1 year but hopefully it is archived and you can find it. There was some math in the thread as I remember.

[garbled]

Are there any good materials that have a known-to-be negative ORP I could use to test with? I don't know that I necc, need to know the ORP value, but just that I'm getting negative vs positive numbers. I have read the post you were referring to, but it was kind of vauge on the details of using the bnc crossover.