Refractometer calibration

[Bolo Tran]

I need to calbrate my refractometer because I think it's way off. I don't have any calibration fluid but is it ok to use distilled water for the time being? Is there a different procedure when using distilled vs calibration fluid? Thanks

 

[Sisterlimonpot]

distilled water will work for the time being. But to calibrate it to your target salinity is much more accurate. Randy Holmes Farley has an article in RK that will help you out. Hopefully someone will chime in for the article

 

[mcoomer]

Use distilled water if you have it. It will be accurate enough for what we're checking with them.

 

[Toddrtrex]

I would order some of the calibration fluid (( or make your own )), to order it it is only $5 or so.

I used to calibrate mine with RO/DI, and when I got the fluid found out that I was off by .02, enough to cause some issues.

 

[mg426]

<a href=showthread.php?s=&postid=14778596#post14778596 target=_blank>Originally posted</a> by mcoomer
Use distilled water if you have it. It will be accurate enough for what we're checking with them.

I cant disagree more. Using RO/DI water only verifys the Zero point of the Refact. You MUST check the span or better said the point at which the inst. is to be used. Get some Pinpoint calibration solution.

 

[HotHotHot]

FWIW, I used to use RODI and after having some serious issues (die off) I found out that my refractometer was off by 5 PPT.

Nothing worse than trusting your instruments only to find out they were calibrated wrong.

Use Randy's recipe or buy some calibration fluid. It's cheap insurance.

Ed

 

[Blown76mav]

What is Randy's recipe? I use RO/DI water with mine.

 

[HotHotHot]

Randy's recipe:

http://www.reefkeeping.com/issues/2004-06/rhf/index.php

 

[Blown76mav]

Thanks

 

[hyperfocal]

Randy's Recipe is good stuff. I found out I was off by almost 3ppt. Be careful when buying pre-packaged calibration fluids, many are intended to be used in electronic salinity testers -- the fluid may have the correct conductivity, but not refract light 'properly'

 

[spleify]

<a href=showthread.php?s=&postid=14778937#post14778937 target=_blank>Originally posted</a> by mg426
I cant disagree more. Using RO/DI water only verifys the Zero point of the Refact. You MUST check the span or better said the point at which the inst. is to be used. Get some Pinpoint calibration solution.

+100000

Use a solution whether it be Randy(that is what I use and have very good success with it) or buy some pinpoint calibration solution.

Do NOT use DI water.

Good luck

 

[chicken]

+1 on HotHotHot's comment. I had some major problems a few years back and lost my favorite eel due to the fact that my refractometer was off by 5 PPT due to the fact that I was only calibrating with DI water. Spend the $5 on the calibration fluid. Do not trust your refractometer.