One of the most frustrating elements of this hobby for me is testing inconsistencies. Even something simple like salinity can trip you up. I keep everything at around 35psu. So I got an oceamo icp recently and the salinity came back as 32.9…. I confirmed that and my salinity probe reads 32.9 but it’s old and I have never really trusted it so I use a digital Hanna tester that was reading around 35psu. I pulled a refractometer and calibrated that to 35psu. That confirmed the low 32.9 salinity as well. So much for Hanna. I did a WC to raise salinity using the refractometer as the master. Now, salinity probe is reading 32.8, Hanna @ 35.6 and the calibrated refractometer at 35psu.. I mean.. it’s the dang salinity for crying out loud. The very base component of a successful tank. I just don’t understand how we have a space station but can’t get a reliable home test for salt content in a body of water..