I was wondering if someone could chime in regarding the Neptune Systems ORP Probe and PM1 Module. I have both and I am currently running through the maturation process of the Deltec NFP509 Nitrate Filter. I would like to run this in Fully Automatic Mode which requires the ORP Probe to be able to read down to -170mv. However, for the last day or so I am getting a zero reading which is what prompted my post. I know the GHL Probes and controller can do this and would rather not mix ecosystems again.
