I have all the probes for my controller, temp, salinity, ORP, pH. The only probe I find useful is the temp probe. It controls the aquarium temp with the heaters and fans.
The other probes, completely useless and a waste of money for me.
ORP - I know what it is measuring but I have no idea what it means
I never pay attention to it.
pH - kinda neat to see but for the price of the probe it really does not add anything useful to me. Been watching my daily pH go from 7.7 to 8.3 for over a year now. I have never done anything with my pH and I don't even notice it anymore.
Salinity - again, neat to see but hardly ever changes plus, with my probe I have to clean and calibrate it often to get an accurate reading. And by often I mean every 3 days. At that rate of maintenance I'm better off just using the refractometer. I used to use it to control my salinity until it failed. Once it got too dirty or miscalibrated it would read a bad (false low) salinity value and try to dump too much salt water to compensate. Thankfully it wasn't a disaster but it was annoying. Even this probe I ignore now because I can't be bothered to clean it as often as it seems to need to be cleaned.
Sorry there may have been a bit of ranting there LOL. Seriously tho if my controller died tomorrow I would get a basic controller (apex or reefkeeper) with a temp probe and network add on and call it a day.