Refractometer Calibration Fluid Question

[GoVols]

I bought a bottle of Use Two Little Fishies AccuraSea and re calibrated my refractometer.

"AccuraSea® Seawater Reference Solution is the only calibration solution of its kind made from real seawater. It’s pure natural seawater micron filtered and UV sterilized then adjusted with reverse osmosis water to match the standard S 35."

My Question is:
Since my refractometer has been calibrated. Can I mix my RO/DI water to 1.025 sg for a water change and bottle some and store my water to be my refractometer's future calibration fluid @ 1.025 sg?

 

[Mr_Banana_Pants]

Just buy a gallon of distilled water and it will be a constant 0 to recalibrate

 

[GoVols]

Just buy a gallon of distilled water and it will be a constant 0 to recalibrate

I've been using my RO/DI water to calibrate to zero. So I've been mixing to that to get my 1.025 sg.
When I bought this calibration fluid it calibrates to 35. When I tested my meter with it, it came to 40.
So I dialed back my meter to 35 and checked it again with the fluid and it was still at 35. I thought my display was holding at 1.025.
After the calibration my display came in at 1.021 sg. So I've slowly raised my display up to 1.025 using my re calibrated meter.

My corals even look better.

So, If I bought distilled water would it be more accurate than calibrating to RO/DI water?

 

[Mr_Banana_Pants]

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

 

[redfishbluefish]

I bought a bottle of Use Two Little Fishies AccuraSea and re calibrated my refractometer.

"AccuraSea® Seawater Reference Solution is the only calibration solution of its kind made from real seawater. It’s pure natural seawater micron filtered and UV sterilized then adjusted with reverse osmosis water to match the standard S 35."

My Question is:
Since my refractometer has been calibrated. Can I mix my RO/DI water to 1.025 sg for a water change and bottle some and store my water to be my refractometer's future calibration fluid @ 1.025 sg?

Shhhhhhh! You're letting folks know this marketing ploy to charge you eight to ten dollars for a couple ounces of saltwater.

I've repeatedly told those who didn't want to spend the cash for calibration solution to simply steal a small vial of tank water from their friend's tank, knowing the salinity from a calibrated refractometer. .......free calibration fluid!

 

[Mr_Banana_Pants]

I work on swimming pools and when I install a salt water chlorine generator I have to add a lower amount of salt then the measurements state to adjust for the sodium in the water before salt

 

[redfishbluefish]

...........So, If I bought distilled water would it be more accurate then calibrating to RO/DI water?

So if you bought calibration fluid it would be even more accurate!

 

[Mr_Banana_Pants]

Shhhhhhh! You're letting folks know this marketing ploy to charge you eight to ten dollars for a couple ounces of saltwater.

I've repeatedly told those who didn't want to spend the cash for calibration solution to simply steal a small vial of tank water from their friend's tank, knowing the salinity from a calibrated refractometer. .......free calibration fluid!

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

 

[redfishbluefish]

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

But you're not measuring water at zero salinity!!!! With any equipment, you want to calibrate closest to what you're measuring. With pH, I don't use pH 4 and pH 7 calibration solutions, I use 7 and 10, because it's closer to what I'm measuring. Same with refractometers.

 

[GoVols]

Thanks to both of you!

I will be storing my calibrated water for future use and or buy some distilled water.

@Mr_Banana_Pants
Thank you for the explanation between RODI and distilled

 

[Mr_Banana_Pants]

But you're not measuring water at zero salinity!!!! With any equipment, you want to calibrate closest to what you're measuring. With pH, I don't use pH 4 and pH 7 calibration solutions, I use 7 and 10, because it's closer to what I'm measuring. Same with refractometers.

I agree, but how can you be sure that the water your testing is 100% 1.025

 

[GoVols]

But you're not measuring water at zero salinity!!!! With any equipment, you want to calibrate closest to what you're measuring. With pH, I don't use pH 4 and pH 7 calibration solutions, I use 7 and 10, because it's closer to what I'm measuring. Same with refractometers.

I agree and that's why I chose a fluid that calibrates to 35.

 

[GoVols]

I agree, but how can you be sure that the water your testing is 100% 1.025

I don't think you can 100%.
I'm at the mercy of the accuracy of the two little fish fluid to be 35.

 

[Mr_Banana_Pants]

I don't think you can 100%.
I'm at the mercy of the accuracy of the two little fish fluid to be 35.

Very very true lol

 

[GoVols]

@Mr_Banana_Pants @redfishbluefish

Thanks again.

I was looking to see if someone said why you can't store your newly calibrated water for future refractometer calibrations.

 

[radicaltour]

Related to this topic, does the typical calibration fluid subjected to evaporation? If so, doesn't it mean the fluid ppt level would increase as it sits on the shelf for months?

 

[Mr_Banana_Pants]

Related to this topic, does the typical calibration fluid subjected to evaporation? If so, doesn't it mean the fluid ppt level would increase as it sits on the shelf for months?

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

 

[radicaltour]

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

 

[Randy Holmes-Farley Verified Community Expert]

I bought a bottle of Use Two Little Fishies AccuraSea and re calibrated my refractometer.

"AccuraSea® Seawater Reference Solution is the only calibration solution of its kind made from real seawater. It’s pure natural seawater micron filtered and UV sterilized then adjusted with reverse osmosis water to match the standard S 35."

My Question is:
Since my refractometer has been calibrated. Can I mix my RO/DI water to 1.025 sg for a water change and bottle some and store my water to be my refractometer's future calibration fluid @ 1.025 sg?

Yes, that will work.

 

[Randy Holmes-Farley Verified Community Expert]

Just buy a gallon of distilled water and it will be a constant 0 to recalibrate

Which will give incorrect calibration for measuring seawater with many refractometers.