35ppt

Okay so Hanna's Digital Salinity Meter requires calibration right? Could Hanna produce a Checker that did not require the purchase of calibration solutions? For example if a Salt Mix Pack says "Mix 1g of salt to 1 liter of water for 35ppt" Bearing in mind Hanna Calibration solution is 35ppt, you...

Are you properly calibrating your refractometer? Lot of people just use RO/DI water which will read 0..however your not going to get the the most accurate results. the next batch of people will use proper 35ppt/1.026 calibration solution which gets you closer.. but ar you taking into account...