Good to see that my initial conclusions are holding up. Thank you for taking time to investigate and report your results. The Hanna calibration fluid is the issue why the the salinity checker gives results that don't match with other methods of checking salinity if calibrated with Hanna solution, but spot on with other calibration options. I haven't touched my tester since I reported my issues and conclusions on the calibration fluid, just can't trust it after all this.I just wanted to post a update for anyone dealing with this.
I purchased 2 things. Tropic Marin hydrometer. It’s the one you float in water and it’s supposedly very accurate.
And 2 little fishes calibration fluid. This fluid is supposedly made from ocean water.
i re calibrated the refractometer with the new fluid And the Hanna with the Hanna calibration packets.
the refractometer and the hydrometer both showed the same number.
then I calibrated the Hanna with the new fluid and then all 3 showed the same result.
i am confident the Hanna calibration fluid is what is causing the problems.
I tested all 3 against different salinity levels and they stayed consistent.
my takeaways are this: the cheap refractometer calibration fluid was either expired or not accurate. The Hanna calibration fluid packets are not accurate for some reason. It might be from other elements that make seawater that change it’s reading that are not present in the calibration packet. I trust the hydrometer the most since its supposedly calibrated in the factory and has no way to be altered at home. It’s dummy proof and provides a clearer reading that my eyes can see in a refractometer.
so for now I will trust the Hanna calibrated with the 2 little fishes fluid and check it periodically against the other 2. My alk and calcium are within the estimates from the salt mix now