what is the sg of fresh ro water?

[meleerock]

like stated above. I want to callibrate my refractometer because i think it is off. what its the specific gravity of RO? Its not heated, and Its an ATC (autoTempControl). will this make a difference?

 

[luca brasi]

Zero

 

[coraljunky]

I use ro to zero mine. But I think the directions say to use distilled. Not sure if it matters though.

 

[dragonzim]

If you are going to calibrate your refracotmeter you should use distilled water. At least, that is what the directions that come with them say. I'd guess that if your TDS meter reads zero on your RO that you would be able to use that as well though.