How to accurately use Milwaukee refractometer MA87 ( I need help)

[Sid2022]

So i went to the fish store in Framingham and they said my salinity is 1.028, I came home and tested my salinity with the Milwaukee refractometer and it says it was 1.024. I ordered a 35ppt control off of amazon to double check my Milwaukee refractometer and it keeps reading 32 or 33 ppt when it's supposed to be 35. What am I doing wrong?

Side note I am using distilled water to Zero as per the directions and to clean the prism. Also the temperature always says 64.7F

Please help

 

[Chris.Reef]

Calibrating it with distilled water is the correct way. What did they use to measure salinity?

 

[Duds]

I wonder if it’s faulty as I doubt you’re running your tank that cold. Maybe reach out to Milwaukee or the place you bought it from to see if they can be of any assistance.

 

[Sid2022]

Calibrating it with distilled water is the correct way. What did they use to measure salinity?

I think they use something called a Lamotte, its that device that tests multiple things at once

 

[Sid2022]

Yeah it should read 35 ppt with the standard I ordered but it keeps saying 32/33 and I'm trying to figure it out

 

[Chris.Reef]

I’m assuming you are letting the temperature level out before you cal and read? Also try and clean the glass window with a q tip