WANTED: ORP meters

Good day water keepers What phone adapter or camera do you use for scrapes. I have chronic Lyme and everything hurts and I don’t want to sit in a stationary position plus I only have one lense for my binocular microscope. I’m becoming very very frustrated with the fish med situation in Canada… Anyone want to ship me this Lernex pro stuff? Also… for ORP meters do they need to be the expensive kind? Lol what do you guys use?

Hi looking for recommendations for a suitable salinity/salt meter to test pond water and to manage levels back down to normal following a recent application of salt to pond for treatment, thanks