Refractometer Calibration Fluid Question

[Randy Holmes-Farley Verified Community Expert]

Yes because Rodi doesn't remove sodium from the water supply

Ridiculous on both points. RO/DI removes sodium ions, obviously, and pure water is not a good calibration for all refractometers.

 

[Randy Holmes-Farley Verified Community Expert]

That works as well... I just like distilled water because it's a guarantee that the Salinity will be 0

But it is definitely not a guarantee that you'll measure 35 ppt correctly. In fact, it DEFINITELY will be off if it is a perfectly made brine refractometer, which many are.

 

[Randy Holmes-Farley Verified Community Expert]

If the container is open then it will evaporate, if it's sealed it should be fine... just be sure it's exactly 1.025 when you put it away

FWIW, the calibration fluid is usually 35 ppt, or sg = 1..0264.

 

[Randy Holmes-Farley Verified Community Expert]

What about the calibration fluid in the tiny bottles? I use it every other day and so i have to uncap it frequently.

Unless you leave it open for more than a short time, it won't noticeably evaporate within the specifications of a typical refractometer.

 

[GoVols]

What about the calibration fluid in the tiny bottles? I use it every other day and so i have to uncap it frequently.

radicaltour, I don't know.
I stopped using the calibration fluid about 3 months ago.
I ran out and got lazy and thougt RODI would be close enough. I won't make that mistake again...

I didn't just pour the salt in display to make up my SG. I made an educated guess on how much extra salt to add, and did a slow 15 gallon (almost drip) water change. My educated (Lucky guess nailed my display from 1.021 to 1.025)

So the extra salt amount I added in my 15 gallons after I hit 1.025 was 7.5 more cups of salt.
On that note: I have have not checked the Big 3 yet, but I figure I wont be dosing them for awhile

 

[GoVols]

FWIW, the calibration fluid is usually 35 ppt, or sg = 1..0264.

I understand that Randy. I just like mixing to the left side of the meter to 1.025 sg.

 

[jason2459]

Similar discussion

http://reef2reef.com/threads/calibrating-a-refractometer.283740/

 

[Mr_Banana_Pants]

Ridiculous on both points. RO/DI removes sodium ions, obviously, and pure water is not a good calibration for all refractometers.

Ro does not remove all sodium in the water supply... up to 90% but it doesn't take into account if the sodium levels are high in your supply (as it can be in wells).

 

[GoVols]

Yes, that will work.

Thank You!

 

[jason2459]

Ro does not remove all sodium in the water supply... up to 90% but it doesn't take into account if the sodium levels are high in your supply (as it can be in wells).

Yes because Rodi doesn't remove sodium from the water supply

You said RODI, he said RODI, now you're saying RO...which would you like to stick with? One of them is wrong.

 

[Randy Holmes-Farley Verified Community Expert]

Ro does not remove all sodium in the water supply... up to 90% but it doesn't take into account if the sodium levels are high in your supply (as it can be in wells).

You had said, and the the OP was using, RO/DI.
RO/DI removes nearly all sodium ions.

 

[Randy Holmes-Farley Verified Community Expert]

I understand that Randy. I just like mixing to the left side of the meter to 1.025 sg.

That's fine. Once calibrated, you can mix to any level you want.

 

[bgoldb]

That's fine. Once calibrated, you can mix to any level you want.

Doesn't temperature come into play here? From my understanding, most refractometers need to be calibrated with solution at 25 degrees Celsius/77 degree F. Please confirm if this is necessary or if any temperature variance is insignificant in the calibration process.

 

[GoVols]

That's fine. Once calibrated, you can mix to any level you want.

That's my plan.

The next water change, I will be mixing to 1.025 and checking my meter to the 35 solution.
Once my new water change water hits 1.025 to my calibrated meter I'm going to store some of it in small clean bottles.

Then, I'll be calibrating the meter to 1.025 with the stored water in the future.

I'm going to store my 35 solution too as my long haul reference point.

Randy, Thanks for your time

 

[GoVols]

Doesn't temperature come into play here? From my understanding, most refractometers need to be calibrated with solution at 25 degrees Celsius/77 degree F. Please confirm if this is necessary or if any temperature variance is insignificant in the calibration process.

Bump