refractometer calibration

I took your advice 3reefers and asked Santa for a refractometer and the elves delivered!


I still have not moved to RODI water... yet. It's in the plan though.

My question is the instructions say to calibrate with DISTILLED water.


I do not have RODI - so what constitutes distilled? Can I use untreated tap to calibrate accurately? Do I need to run up to store to get a bottle of distilled?

Basically, for calibrating and cleaning, is tap fine for a refractometer? I haven't used it yet, waiting on an answer here.

Thanks!

 

best to buy distilled from store. just make sure it says distilled

 

It is better to use RODI. Distilled water is not guaranteed to have 0 TDS. Usually big grocery chains sell RODI by the gallon in the same section as the other drinking waters. RODI has undergone a much more complete process of filtration and sterilization than distilled.

That being said, congratulations on your refracto. You will love it. They are so easy to use and calibrate. They are also far more accurate than hydrometers. Most autocorrect for temperature as well--I also have a TDS meter but I use my refracto 100% of the time.

 

Best to use SALINITY CAL FLUID 53.0MS
53.0ms will equal 35PPT or 1.0265 SG which ever your refractometer reads.

 

Thank you Otty for the info. I was a bit confused as to how to use the calibration fluid my wife so thoughtfuly picked up with my NEW refractometer

 

When you put the fluid on the meter let it sit for about 30 seconds if it is a ATC (Auto Temp compensate) so you get a accurate reading. I never trusted just using water to calibrate.

 

That calibration solution. What is the best one in your opinion? I used distilled for the time being, 99.99% pure, and I do believe that to be not as acurate as usina calibration solution. Kudos for the refractometer, too many dip and drips with the hdyrometer.

 

How often do these need calibrated? Each time, monthly, annually? The manual didn't give any indication after the first calibration.

 

I use calibration solution to calibrate mine. Since I use RODI, I "check" the calibration every time I use it. If it reads anything other than 0, then I pull out the calibration solution and calibrate it to 35ppm. Even though I check it everytime I use it, I rarely have to adjust it (maybe twice in the past 2 years.) I would say if you are calibrating it once every 3-6 months you will be fine.

 

Mine has a locking nut so I only do it ever few months or if I bump or drop the meter.