need your thoughts on Refractometer calibration

[Black71gp]

I like the idea of 50/50 mix I think i will aim for that for calibration for the treatment

[MizTanks]

Alternatively, you could purchase a laboratory grade refractometer that is linear from 1.000 to 1.040 or get a calibration fluid that measures 1.010 and use the current refractometer.

See right up there^^^


There is nothing like being a REEFER!

[BeakerBob]

Ummmm still don't understand sorry. What is meant by " calibrate it to 1.040b

Alternatively, you could purchase a laboratory grade refractometer that is linear from 1.000 to 1.040 or get a calibration fluid that measures 1.010 and use the current refractometer.

See right up there^^^

Most of the inexpensive refractometers are not linear from 1.000 to 1.040 (or higher). This means that they are not accurate in the whole range of measurement. That's why you cannot calibrate it with RO water (1.000) and expect it to measure accurately to 1.026, the normal reading of SW. You need to calibrate these types of instruments at or near it's point of use.

A good laboratory grade refractometer is linear from 1.000 to 1.040 (or higher), so that you can calibrate with water at 1.000 and it is still accurate to 1.040. Conversely, you could calibrate at any point and it would be accurate throughout its measuring range.

[fishtal]

Much better in quality!! This one should perform like you want.

Good to know. That's the one I have.

[jenghes]

Here is a great article on refractometer calibration and it gives directions on how to make calibration fluid.

http://reefkeeping.com/issues/2006-12/rhf/index.php