Which salinity to trust?

[tmccaff]

I just calibrated all 3 of my equipment for checking salinity. Hanna checker shows 33.8 ppt(78 degrees temp); My VEE-GEE shows 34ppt and my GHL probe shows 36.8 (77.1 degrees temp). I used 53ms to calibrate probe maybe why? When I checked hanna with solution it showed 34.2 and GHL 35.0

 

[Cell]

I go with the middle reading and use the VeeGee as the primary measurement going forward.