Refractometers

[shibumi]

I have been looking for a refractometer and I see different kinds.

And my question is:

What is the difference between 0-10% and 0-28% and which one we need?

 

[alizarin]

Beautiful pictures! Whatkind of setup do you have?

 

[Kubi]

rhs-10atc Pet Mart has them or they did. I used my receipt points up and got for about $40.00. Have them calibrate it to. I also bought one from Marine Depot once and it was a piece of crap. It rusted away....lol