Refractometer solution

[nxb161]

I finally got myself a refractometer, and before I had a chance to calibrate it, one of my pups found the solution.... It must have rolled off the shelf when I went to feed them. I am pretty sure this is just distilled water (that is how the manual described it) is that true? can I just go to the supermarket and pick up a jug of distilled water (not htat i'll need that much)

 

[melosu58]

That`s all I do is put some RO/DI water on there and calibrate it.

 

[neilanh]

Same for me, just RODI water to calibrate it.

 

[HN1]

Agreed and the pup should be fine.

 

[Kurt_Nelson]

Calibrating with RO/DI just makes sure that it reads 1.000 correctly. I'd suggest calibrating it using something like this:

Aquarium Testing Solution: American Marine Inc. 53.0 mS Calibration/Reference Fluid

Using this, it will calibrate to 35ppt which is between 1.026 and 1.027. Refractometers are not neccesarily linear... just because they read zero accurately does not mean they read at 1.025ish accurately. Better to calibrate them in the range you intend to use them.

(PS... even if what was supplied was the solution I linked to, the puppy will be just fine.)

 

[thincat]

Just brush his teeth to prevent coralline growth.

 

[ccCapt]

Kurt got it.
Our refractometer are made to measure saltwater not seawater, which is what's in our tanks. The fliud Kurt linked to is a seawater calibration solution and it's what you should use to accurately calibrate your refracto for measuring seawater.

Refractometers and Salinity Measurement by Randy Holmes-Farley - Reefkeeping.com
"Fortunately for aquarists, the differences between a salt refractometer and a seawater refractometer are not too large. A 35 ppt sodium chloride solution (3.5 weight percent sodium chloride in water) has the same refractive index as a 33.3 ppt seawater solution, so the error in using a perfectly calibrated salt refractometer is about 1.7 ppt, or 5% of the total salinity. This error is significant, in my opinion, but not usually enough to cause a reef aquarium to fail, assuming the aquarist has targeted an appropriate salinity in the first place. "

 

[cabezon]

Just brush his teeth to prevent coralline growth.

 

[thincat]

 

[ryshark]

I am with Kurt and ccCapt on this one. I used to use distilled or ro/di water to calibrate my refractometer. Then when I got a calibration solution I realized how far off I was. It was off by .003..... If I remember correctly I thought I was at 1.025 but I was really at 1.022
I like this one Aqua Craft Refractometer Calibration Fluid - English
because it comes with a built in dropper as you can see in the picture and I think it evaporates less than the Pinpoint. Plus I think the Pinpoint solution is designed for calibrating probes.

 

[thincat]

ryshark, thanks for the link.