Get one of these and you're set for life (assuming you don't break it, lol). No calibration needed, only slight calculation for temp above/below 77F.
High Precision Hydrometer
Ensure that your equipment is reading correctly and your aquarium is at the right salinity with Tropic Marin's High Precision Hydrometer. Many tank inhabitants are sensitive even to minor changes of the water conditions. Unfortunately as we've all experienced, salinity reading equipment as...
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