Refractometer Calibration?

[Aspect]

How often should a refractometer need to be calibrated, I need to do so every couple of days, is this normal?

 

[Oscar47f]

Yes it’s normal, sometimes they will hold a calibration but they’re temperature sensitive so best practice is to calibrate daily

 

[gbroadbridge]

How often should a refractometer need to be calibrated, I need to do so every couple of days, is this normal?

I check calibration each time I use one - but that's not often as if you have a working ATO and no leaks, the salinity should be reasonably stable.

Once every couple of weeks does it for me to adjust for the rise due to 3 part dosing.