Trying to establish which probe is which socket if that makes sense, I use 1 x Orp and 1 x pH. The pH is connected to the dedicated pH marked socket on the Apex head units, all is OK here. However as I have a PM1 module as well there is a total potential of pH sockets as follows:

1: ph on head unit: connected to ph probes and works fine
2: orp/ph on head unit: has this issue
3: orp/ph on PM1: has this issue

Basically in Classic if I enable the problem and them click update it looks like it worked however if I them click on another probe and back to the one just enabled it is now disabled. Same for both No2 and No3

Any ideas ?