Refractometer question

[double_g2k]

How do you calibrate a refractometer? I don't have RO and am saving up for a unit. Should I go buy a gallon and test it? Both the water in my tank and the water in a friends tank are measuring 1.020 and tap water is almost zero for salinity so it SOUNDS like it['s doing its job, but can it stay calibrated forever?
FYI my hydrometer says the SG is 1.025 so boy am I happy I got one of these!

 

[pontius]

you calibrating it by making sure that tapwater reads 1.000. if it's saying "almost zero", then it's not calibrated.

 

[double_g2k]

doesn't tap water contain trace amounts of salt? Would RO water be a better calibration option if I can go out and buy a gallon of it?
Thanks for the quick reply btw

 

[scsinet]

Yes, RO or Distilled is a better choice than tap water. The BEST choice is a calibration fluid, but that is unnecessary.

 

[double_g2k]

Sweet. Ok Thank you SCSInet