Distilled or RO water for calibration

[Speedway_06]

The directions for this refractometer I bought says to used distilled water to calibrate. Would plain RO water (TDS 11) work just as well?

 

[kayne_21]

Personally I would use the pinpoint calibration solution for it. http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+4416+18717&pcatid=18717

Calibrate the refractometer to 35ppt with that stuff.

Using distilled and RO/DI my refractometer was off by .006 compared to the calibration solution.

 

[GBE378]

I agree with kayne. Use a calibration solution. They are easy, accurate and cheap.

 

[robsee06]

Check the reef chemistry forum. You cannot accurately calibrate a refractometer with RO or distilled water. Get the calibration somution described above.

 

[vanmo92]

definitely the calibration solution. Although I do think that Distilled would be better than RO.