Refractometer Calibration - Lesson Learned

[Dresden]

Thought I'd share a lesson learned recently.

I didn't know you should calibrate your refractometer with a special solution. I'd been using tap water for decade without realizing it. I had usually kept a pretty simple tank until recently.

Bought the calibration fluid and realized I had been running at less than 1.020. Slowly correcting to 1.025 now but I wanted to share in case it helps someone.

Maybe it is time to move to a digital salinity checker? Recommendations?