Salt calibratrion question

[spud71]

I too have a marine depot $39 refractometer. It disagrees with my JBJ Digital Salinity meter that seems to go out of calibration easily too and also with my LFS refractometer.

I wish to use your bottle of coke/salt trick but my hopefully not too stupid question is that my wife bought Morton Salt, but it appears to be the un-iodized type.

Not being a chemist of any measure, does this make any difference or does it have to be the iodized type?

Thanks

 

[Randy Holmes-Farley]

I do not expect the iodine impacts it, since it is a very minor ingredient. Let's see how that turns out before worrying about it.