larryd:
These are 'signal amplifiers' where the input to output is physically isolated from each other.
These isolated your transducer analog signals from a controller, PLC etc.These are similar to what an optoisolator does for digital signals.
the really confusing part is that the ph sensor module is still grounded to the main psu wouldnt the probe get a ton of interference from the mains noise in the water even if the signal at the arduino was isolated? wouldnt i have to isolate everything? sorry im just really confused right now. besides what you showed me. the closest thing I found was this https://www.dfrobot.com/product-1621.html. i figured maybe i could power the whole ph sensor circuit with this and get isolated ground and signal?