how to calibrate refractometer dilemma

[mark freshwater]

Hi,
I received my refractometer today in the post,
The instructions state to calibrate it with distilled water, is this correct ?
I have read that you should calibrate it with proper salt calibration fluid.
But you would think the manufacturing company would know.
Also it says if it has ATC (which it does) to make sure the ambient room temp should be 20 degrees Celsius, 68f , and if room temp changes by 5 degrees Celsius to recalibrate.
how am i surposed to make the room this temp far out.
Any help please .
This is the one http://www.aquariumonlinesupplies.com.au/microbe-lift-refractometer-1-3mag.html

 

[Dr. Reef Verified Sponsor]

i would buy a salinity standard. Two little fishies make a salinity calibration standard,
i would bring the refrac and salinity standard inside the house and keep it at whatever temp your house is usually 74-78F. Leave both items at room temp for a while then calibrate. once calibration is done then you can use it for any temp or salinity and should be within accuracy.

 

[mark freshwater]

ok great thanks,
so the exact temp doesnt matter to much at the start?
i guess i could turn the aircon onto desired temp and shut the doors .

 

[Dr. Reef Verified Sponsor]

Once you have calibrated the refractometer at right temp witg right standard it will automatically adjust for hotter or cooler samples as long as you place the sample water on prism and let it sit for a min or 2 for it to adjust.
My setup is in my garage and its 140F during summer and freezing during winters. I take my standard solution and refrac inside home at 76 for multiple hours to calibrate then bring it back out and use it for my tank water or makeup water.

 

[mark freshwater]

ok great thanks