calibrating refractometer

Just had an issue with my Hanna tester that would not stay calibrated long enough to test my water. Hanna said they’d send me a new one. Well, this turned me off on their products so I bought this Milwaukee MA887 from all the reviews on it and how it NEVER FAILS... I bought it brand new and...

It is very simple, but I forgot to do it. After 10 years of my red sea max 130d, reading, testing and learning a lot, I set my 100 gallon tank 70 days ago. Since the beginning I tested a lot... Followed day by day the cycling process, adding fish, corals and etc. I prepared a sump with UV...

I have just bought some brightwell calibration fluid for my refractometer, I use to use acurasea but I couldn't get more of that. With acurasea it said my tank was always at 1.025 salinity but now I have calibrated with brightwell it says I am well under that. This is what it reads with the new...

ok so i bought a refractometer because i wanna get pinpoint accuracy of my tanks salinity and i have a few questions. ok so first of it’s a fairly old refractometer it looks to be sitting on that shelf for a while will that affect how it works i opened it up and it looks brand new though. also...

I just opened up my new refractometer and out of the box it's saying my RO/DI water has 0ppt / 1.0 SG and my tank has 1.027 SG. Should I even bother trying to calibrate this? Some of the Amazon reviews state they took it straight to the LFS to test and theirs were already calibrated...