I use the digital Hanna checker, so far so go.. I really do like it. I kept my refractometer just to check and the Hanna is spot on..I even when one step further and had salinity checked at my lfs and all good...
I have been using my $5 Coralife hydrometer for the past 10 years , it’s simple and always provided an accurate reading (I check each year with a refractometer, and each year is the same exact reading):
I’m quite surprised to see so many still using hydrometer. Stopped using those over a decade ago - all the ones I had were crap. If I want a periodic accurate and precise reading, I use a good quality, calibrated refractometer. I do use the apex salinity module for continuous monitoring (more for changes than absolute accuracy).
Bumping this one up being my Milwaukee MA887 is driving me a little crazy right now. I calibrate with the provided distilled water to get to 1.000 SG. Then I run a test with the provided 1.025 solution and get 1.027.....
The meter is saying my tank is currently 1.024. I'm not sure what to trust right now. Anyone else have this experience? I guess I need to order a scale to make my own calibration solution from now on.