ORP/pH/Temp Probe Placement

[JohnS_323]

I was talking to a fellow reefer about my inability to get my ORP up over 310. I have an AquaController II and he mentioned that all three probes needed to be within 3 inches of each other. I did some checking and that seems to be the case (something about the temp probe being the ground for the other two). The question I have is, do all three probes have to be in the SAME water source? More specifically, my pH probe is in a cup in my sump that monitors the efluent flow from my Ca reactor. Can I put the temp and ORP probe in the sump right next to this cup? or do all three have to be in the cup?

Any insight would be appreciated.

TIA.

 

[bertoni]

If they all have to be within three inches of each other, which sounds strange to me, they all need to be in the same water source.