calibrate refractometer w/ RO/DI water?

The directions say to use distilled water. Would it be ok to use bottled (drinking water)? Or RO/DI water?

 

Use ro/di water to calibrate.

 

Use ro/di that has been tested to 0 TDS.

 

Rodi d:

 

Is absolute zero required?

 

Technically: yes.

In all actuality - you might get away with it a little above zero - but in my mind - not worth the risk.

Only way to ensure your are totally acurate is to use 0 TDS water.

RO/DI that has been verified by a calibrated TDS meter can be used.

I did calibrate my refracto with distilled the first time and got a reading right away with no adjustment of 0 for salinity.

 

If your refractometer is a salt water refractometer, and if you use distilled or RO for calibration, the reading will be off at normal reef salinity.
If you have a seawater refractometer you will get a correct reading.
To be safe, use a calibration fluid in the range you keep your reef at.
Refractometers and Salinity Measurement by Randy Holmes-Farley - Reefkeeping.com
Reef Aquarium Salinity: Homemade Calibration Standards by Randy Holmes-Farley - Reefkeeping.com