Randy Holme’s DIY refractometer fluid

[Mhoover1481]

New to Reef2Reef, and hope this is allowed.

I am having salinity issues after being in the hobby for about a year now.
My refractometer’s (new and old) are reading wonky. And I have calibrated with 35ppt solution from BRS and AccuraSea, different readings from Both and NOT 35 ppt.

I am reading up on Randy Holmes diy solution using NaCl and purified water.

I have the tools and supplies to make this solution, but I’m trying to understand the science.

In theory, if I do his recipe, the NaCl fluid reading should be 1.3394 on the refractometer, and that equates to 35 ppt seawater, right?

So, I should make his calibration fluid, put it on the refractometer, if it says 1.3394 ish, I should calibrate my refractometer to 35ppt and then I should be getting accurate readings?

I’m having some trouble understanding

Thanks!

 

[twentyleagues]

New to Reef2Reef, and hope this is allowed.

I am having salinity issues after being in the hobby for about a year now.
My refractometer’s (new and old) are reading wonky. And I have calibrated with 35ppt solution from BRS and AccuraSea, different readings from Both and NOT 35 ppt.

I am reading up on Randy Holmes diy solution using NaCl and purified water.

I have the tools and supplies to make this solution, but I’m trying to understand the science.

In theory, if I do his recipe, the NaCl fluid reading should be 1.3394 on the refractometer, and that equates to 35 ppt seawater, right?

So, I should make his calibration fluid, put it on the refractometer, if it says 1.3394 ish, I should calibrate my refractometer to 35ppt and then I should be getting accurate readings?

I’m having some trouble understanding

Thanks!

My understanding is if it reads 1.3394 then leave it alone. If it does not adjust it to read that. Then you are calibrated.

 

[Mhoover1481]

My understanding is if it reads 1.3394 then leave it alone. If it does not adjust it to read that. Then you are calibrated.

So essentially, I would want my salt mix to test @1.3394 everytime to know that it’s actually 1.026?

 

[Mhoover1481]

New to Reef2Reef, and hope this is allowed.

I am having salinity issues after being in the hobby for about a year now.
My refractometer’s (new and old) are reading wonky. And I have calibrated with 35ppt solution from BRS and AccuraSea, different readings from Both and NOT 35 ppt.

I am reading up on Randy Holmes diy solution using NaCl and purified water.

I have the tools and supplies to make this solution, but I’m trying to understand the science.

In theory, if I do his recipe, the NaCl fluid reading should be 1.3394 on the refractometer, and that equates to 35 ppt seawater, right?

So, I should make his calibration fluid, put it on the refractometer, if it says 1.3394 ish, I should calibrate my refractometer to 35ppt and then I should be getting accurate readings?

I’m having some trouble understanding

Thanks! @Randy Holmes-Farley

 

[twentyleagues]

So essentially, I would want my salt mix to test @1.3394 everytime to know that it’s actually 1.026?

You are making a standard. If you make the standard properly it is 1.3394. When you use it on the refractometer if the refractometer reads it as 1.3394 then the refractometer is properly calibrated. If the refractometer does not read 1.3394 adjust the refractometer to read 1.3394. At that point the refractometer is calibrated. Now you can test your salt water and adjust to your desired salinity by adding more salt or fresh water to whatever salinity you are trying for. You want the salt water to read 1.026. The 1.3394 standard is just a calibration tool. There should be a little screw on the refractometer to physically adjust the scale. After putting the standard on the refractometer if it does not read 1.3394 adjust the screw until it does read 1.3394 then it is calibrated.

 

[dansyr]

New to Reef2Reef, and hope this is allowed.

I am having salinity issues after being in the hobby for about a year now.
My refractometer’s (new and old) are reading wonky. And I have calibrated with 35ppt solution from BRS and AccuraSea, different readings from Both and NOT 35 ppt.

I am reading up on Randy Holmes diy solution using NaCl and purified water.

I have the tools and supplies to make this solution, but I’m trying to understand the science.

In theory, if I do his recipe, the NaCl fluid reading should be 1.3394 on the refractometer, and that equates to 35 ppt seawater, right?

So, I should make his calibration fluid, put it on the refractometer, if it says 1.3394 ish, I should calibrate my refractometer to 35ppt and then I should be getting accurate readings?

I’m having some trouble understanding

Thanks!

exactly what twentyleagues was saying about you making standard and adjusting (calibrating) refractometer to read what the standard says.

But what I want to add is that temperature plays in here and can easily be the variance between different readings, if different devices account (or don't) for Temp differently. Some refractometers have different ways of accounting for temperature, but when going crazy trying to cross-check with multiple devices, manually removing temperature from the equation helps.

For this reason I just keep my 50ml falcon tube of Randy's DIY standard (and another tube of DI for two-point) bobbing in an overflow chamber so it's always at tank temperature if I need it. I don't check salinity THAT often but definitely recommend this if you're going through a period where you're not confident what true salinity is.

 

[red_peanut]

Normal room temperature ranging from 65ish to 75ish should not be a factor. It matters only in extremely cold or hot temps. For our purposes as hobbyists it's fine.