Refactometer - Calibration & Use ?

[westwind77]

I finally picked up a Refractometer and I have a few questions.....
Do I need to use 'distilled water' to calibrate the unit or can I used water that has been run through my API tap water filter?
As far as temp is concerned what is the best way to handle the calibration? The air temp of my house is 68-70, aquarium water is 79, and water out of the API filter is around 50 (guessing).
Should I pull a sample from each, let them adjust to room temp, then calibrate, then measure after the 30 seconds they recomend?
Want to do it right and get the salt right. Swing arm shows 1.023, but curious what it really is.
Thanks!

 

[heart & sole]

i would use distilled water at room temp perferable tank water temp to calibrate it. I used RO water that i put in a plastic bag and stuck inside the tank for about 30 mins to calibrate mine.

 

[bang guy]

For calibration purposes the temperature of the water is irrelevant. You need the refractometer to be at a cooler room temperature to be most accurate.
The best water to calibrate with is 35ppt salinity calibration fluid. If you can't find that then RO/DI, or even RO water will work just fine. Most tap water will be close enough for hobby purposes but it won't be exact.