Refractometer calibration solutions

[Spar]

Which refractometer calibration solution do you believe to be the most reliable and long lasting?

I ask because I have had consistent trouble with most in-bottle brands increasing in salinity in the bottles over time (obviously due to inevitable evaporation). Ones in foil packs such as Milwaukee perhaps wouldn't have this issue but is pricey per calibration (if done frequently anyway, and relative to a single bottle that drips drops), but I am unsure if this is for sure true.

 

[Old Fritz]

I always used filtered or rodi water and calibrated it to zero and never had problems

 

[Peace River]

Which refractometer calibration solution do you believe to be the most reliable and long lasting?

I ask because I have had consistent trouble with most in-bottle brands increasing in salinity in the bottles over time (obviously due to inevitable evaporation). Ones in foil packs such as Milwaukee perhaps wouldn't have this issue but is pricey per calibration (if done frequently anyway, and relative to a single bottle that drips drops), but I am unsure if this is for sure true.

Every one has their own opinion, but one of my frustrations was the limited lifespan of the solutions (as you mentioned) and I have always been wary about simply calibrating to zero (may or may not be an issue) so I personally have used the DIY approach in the Randy Holmes-Farley article - Reef Aquarium Salinity: Homemade Calibration Standards.

 

[road_runner]

I use redsea refractometer. Its suppose to be made to be calibrated with rodi which you always have access to.
I do not trust 35ppt solution 1 week after I open them.
I usually measure my water mix twice. One with redsea after i calibrate it with rodi then with Milwaukee just to make sure it's not too far off. If diffrence is 1 or 2 ppt I trust the refractometer, if diffrence more I recalibrate

 

[Phil D.]

Surprisingly enough, I'm using Calibration solution from Aquacraft products. I have checked cal using it and then with RO/DI water and both methods show my refractometer is calibrated. The solution I have is like a year old!!

 

[road_runner]

I have heard randy do not recommend calibrating with rodi rather 35ppt cause it's closer to the target range. But when I asked redsea they told me our refractometer are designed to provide good accuracy if calibrated by rodi..

 

[Spar]

Thanks for the info on the red sea refract. I ordered one of these. I agree trusting RO/DI water is way more reliable than any solution.

 

[SPR1968]

I have heard randy do not recommend calibrating with rodi rather 35ppt cause it's closer to the target range. But when I asked redsea they told me our refractometer are designed to provide good accuracy if calibrated by rodi..

+1 to this, that’s what Red Sea say

I have calibration fluid at 35ppm and have tried it, and the result is the same as when using RODI so I just use that. Just remember to wipe the screen with your shirt, it’s mandatory! Lol

 

[road_runner]

+1 to this, that’s what Red Sea say

I have calibration fluid at 35ppm and have tried it, and the result is the same as when using RODI so I just use that. Just remember to wipe the screen with your shirt, it’s mandatory! Lol

100% if you calibrate correctly(25c temp, rodi and refractometer both at that temp) your 35ppt solution will read 35ppt otherwise the solution might have something wrong..
As you said, always remember to clean with rodi after use, then wipe clean the glass gently.
I calibrate every time I use the instrument..

 

[SPR1968]

100% if you calibrate correctly(25c temp, rodi and refractometer both at that temp) your 35ppt solution will read 35ppt otherwise the solution might have something wrong..
As you said, always remember to clean with rodi after use, then wipe clean the glass gently.
I calibrate every time I use the instrument..

Yes, and I’ve found if you apply the RODI/Saltwater and wait around 10 seconds the temperature adjusts and the readings are more consistent. The thing is just so sensitive!

To be honest I don’t use it much these days as I have Apex and I calibrate Apex to the Red Sea refractometer which I trust, rather than the other way around

 

[road_runner]

Yes, and I’ve found if you apply the RODI/Saltwater and wait around 10 seconds the temperature adjusts and the readings are more consistent. The thing is just so sensitive!

To be honest I don’t use it much these days as I have Apex and I calibrate Apex to the Red Sea refractometer which I trust, rather than the other way around

i was never ever successful in getting my apex salinity prob to stay. I calibrate, it run well for couppe of days then it start shifting down ha ha.
What do you meam calibrate your prob to the redsea..how do you do that?

 

[Potatohead]

TLF Accurasea

 

[SPR1968]

i was never ever successful in getting my apex salinity prob to stay. I calibrate, it run well for couppe of days then it start shifting down ha ha.
What do you meam calibrate your prob to the redsea..how do you do that?

I wait/adjust the tank water until I’m happy that it’s at 35ppm with my trusty Red Sea refractometer

I then go into manual Apex salinity probe calibration, follow the instructions, wait for a few minutes at each stage to settle, but when it says place into the calibration fluid, it goes back into the tank and water.

Then it matches the refractometer which I trust. I could just never calibrate it to a point I trusted it with the fluid. As you know, it’s more about stability than the actual number, as long as it’s there or thereabouts.

Around every 3-4 months the salinity probe freaks out and tells me it’s 45ppm or something, usually when I’ve just landed, or relaxing abroad in a hotel! Lol. That means it’s time to clean the probe.

 

[road_runner]

I wait/adjust the tank water until I’m happy that it’s at 35ppm with my trusty Red Sea refractometer

I then go into manual Apex salinity probe calibration, follow the instructions, wait for a few minutes at each stage to settle, but when it says place into the calibration fluid, it goes back into the tank and water.

Then it matches the refractometer which I trust. I could just never calibrate it to a point I trusted it with the fluid. As you know, it’s more about stability than the actual number, as long as it’s there or thereabouts.

Around every 3-4 months the salinity probe freaks out and tells me it’s 45ppm or something, usually when I’ve just landed, or relaxing abroad in a hotel! Lol. That means it’s time to clean the probe.

This is brilliant..I never thought of this..
Thanks for sharing

 

[SPR1968]

This is brilliant..I never thought of this..
Thanks for sharing

Your welcome!

I hope it works now! Lol

 

[road_runner]

Your welcome!

I hope it works now! Lol

Unfortunately it's too late. Am now on ghl and loving it.
But always good to.learn something new ha really thank tou

 

[Randy Holmes-Farley Verified Community Expert]

Which refractometer calibration solution do you believe to be the most reliable and long lasting?

I ask because I have had consistent trouble with most in-bottle brands increasing in salinity in the bottles over time (obviously due to inevitable evaporation). Ones in foil packs such as Milwaukee perhaps wouldn't have this issue but is pricey per calibration (if done frequently anyway, and relative to a single bottle that drips drops), but I am unsure if this is for sure true.

That should not be an issue if you keep them properly closed except when using them. Very little evaporation (in our context) takes place through most closed plastic or glass containers.

 

[Randy Holmes-Farley Verified Community Expert]

+1 to this, that’s what Red Sea say

I have calibration fluid at 35ppm and have tried it, and the result is the same as when using RODI so I just use that. Just remember to wipe the screen with your shirt, it’s mandatory! Lol

A true seawater refractometer that is made perfectly and is still functioning perfectly will be able to be perfectly calibrated with RO/DI.

Any refractometer, seawater or brine, made perfectly or not, partly broken or not, can be calibrated with 35 ppt standard and will then correctly read 35 ppt tank water. The only exception is some electronic ones that forbid using a standard, but then you can always check them in the standard, if not actually calibrate.

So the thing is, do you trust your device was made perfectly and still functions perfectly, or would you instead prefer to just use a standard?

I see zero reason to ever use RO/DI, even if it might be OK.

 

[Phil D.]

Adding to my earlier post, I use the solution AND RO/DI. I have a Red Sea Refractometer and it comes out the same on both, zero with RO and 35ppm with the solution.

 

[road_runner]

A true seawater refractometer that is made perfectly and is still functioning perfectly will be able to be perfectly calibrated with RO/DI.

Any refractometer, seawater or brine, made perfectly or not, partly broken or not, can be calibrated with 35 ppt standard and will then correctly read 35 ppt tank water. The only exception is some electronic ones that forbid using a standard, but then you can always check them in the standard, if not actually calibrate.

So the thing is, do you trust your device was made perfectly and still functions perfectly, or would you instead prefer to just use a standard?

I see zero reason to ever use RO/DI, even if it might be OK.

Randy which 35ppt solution tou recommend? Woild be nice to know if you have a preference..