Refractometers and the color of light used: important!

[Randy Holmes-Farley]

Awesome and thank you! The refractometer didn't come with instructions. Lol. What about the calibration fluid? Should I be using it?

Rich

Calibrate any refractometer (except certain digital ones) with a 35 ppt (sg = 1.0264) seawater standard. That can never lead to incorrect readings (assuming the refractometer allows that, a digital one might now allow it), while calibration with RO/DI water can lead to errors.

 

[Randy Holmes-Farley]

Interesting.
I have a related question...
My ATC refractometer says it must be calibrated at a room temp of 74F. Since all there is in the house is a swamp cooler, this is difficult. Is there a way to adjut the calibration for temperature differences?

It makes no sense to me.

Here's a thread where I'm asking BRS about that:

https://www.reef2reef.com/forums/bu...tometer-calibration-temperature-question.html

A number of folks have told me that the ATC refractometer that they've gotten from you says it should be calibrated at 68 deg F.

What possible reason could there be for doing that?

If the ATC works, it won't matter what temp you use for calibration, and if it isn't working perfectly, you'd want to calibrate at the same temp that you measure.

Can you clarify what these directions mean?

TIA

 

[Randy Holmes-Farley]

I hadn't given that a thought! Oops! I calibrate in the basement and the main floor. Looking outside, using the light coming into the room. Sometimes using the different systems' lights (T5's). Et cetera... I have just always looked for the brightest light available at the time of calibration! No wonder every time I check to see if its calibrated, I need to change it! Thanks Randy!!

Thanks, Terri Ann. Glad it was helpful.

 

[ksanfranfan]

Another thank you from a fellow reef hobbyist! It never gets old learning something new in this hobby.

 

[KorD]

This is a great post, and makes a lot of sense... I have learnt this lesson a few years ago as a home brewer using a refractometer..

 

[terri_ann]

Thanks, Terri Ann. Glad it was helpful.

You are such a wealth of information and so very helpful to everyone Randy! By the way, I am using Sybon's Salinity standard but haven't had a chance to compare the 3 bottles I ordered. Hopefully the margin of error with Sybon will be a lot less than the other 2 brands I tested (yes, the same terri ann from RC...lol) Hugs my son! lol