DIY apex conductivity csliv

[Miami Reef]

 

[Miami Reef]

Grr. It’s supposed to say calibration.

@Randy Holmes-Farley Will this recipe work? 6.2g Morton Iodized salt into 182g water?

 

[homer1475]

Isn't that Randy's article?

 

[homer1475]

http://reefkeeping.com/issues/2004-06/rhf/index.htm

 

[Coolcasino]

6.2g Morton Iodized salt into 182g water?

Can this be used for refractometers, the Hanna salt checkers and the Apex conductivity probes?

 

[Randy Holmes-Farley Verified Community Expert]

It is my article and it certainly works if done properly, but one must use the appropriate solution for each device type.

I give them all here:

Reef Aquarium Salinity: Homemade Calibration Standards by Randy Holmes-Farley - Reefkeeping.com

 

[Gtinnel]

Can this be used for refractometers, the Hanna salt checkers and the Apex conductivity probes?

Randy’s article has different recipes wether the salinity tester is a refractometer or a conductivity type.
I make and use both to verify my digital refractometer or Hanna salinity checker. I have never used the conductivity solution on my apex probe yet, but I don’t see why it wouldn’t work.

 

[Coolcasino]

Care to share what those are? Like what do you make for the 1 for the Hanna? You don't use a regular refractometer?

 

[Randy Holmes-Farley Verified Community Expert]

Care to share what those are? Like what do you make for the 1 for the Hanna? You don't use a regular refractometer?

I posted the article with the recipes above.

 

[Coolcasino]

So to calibrate a refractometer 3.65g of morton's and 96.35g of water?

 

[Randy Holmes-Farley Verified Community Expert]

So to calibrate a refractometer 3.65g of morton's and 96.35g of water?

Yes:

efractometer Standard

It is widely believed that only pure water is required to calibrate refractometers. That fact is true of many refractometers, and is certainly appropriate for routine calibration, but it assumes that they were manufactured correctly and have not been damaged since manufacturing. As refractometers used by aquarists become less and less expensive (with some now selling for less than $30), there is every reason to believe that at some point they will no longer be accurate enough.

The only way to be sure that a given refractometer gives useful information is to check its accuracy in a solution similar to aquarium water. I believe that all refractometers should be checked in this fashion when first purchased, and again any time there is a reason to be concerned. For example, an aquarist might be concerned if an aquarium that had been running for years at a salinity of 35 ppt suddenly reads 39 ppt.

In order to provide a standard for refractometers, a solution whose refractive index is similar to normal seawater is required. Seawater with S= 35 has a refractive index of 1.3394.1 Likewise, the refractive index of different sodium chloride solutions can be found in the scientific literature. My CRC Handbook of Chemistry and Physics (57th Edition, Page D-252)4 has such a table. That table has entries for 3.6 and 3.7 weight percent solutions of sodium chloride that span the value for normal seawater. Interpolating between these data points suggests that a solution of 3.65 weight percent sodium chloride has the same refractive index as S=35 seawater, and can be used as an appropriate standard (Table 2).

This 3.65 weight percent sodium chloride solution can be made by dissolving 3.65 grams of sodium chloride in 96.35 grams (mL) of purified fresh water. That amount roughly corresponds to ¼ cup (73.1 g) of Morton's Iodized Salt dissolved into 2 liters (2000 g) of water (giving very slightly more than 2 L of total volume).

 

[Coolcasino]

How long do you think the solution will be good for if?

 

[Randy Holmes-Farley Verified Community Expert]

How long do you think the solution will be good for if?

Probably until the sun goes into an expansion mode and envelopes the earth in a ball of fire. I think that is predicted for a few billion years from now.

Of course, you need to keep it from evaporating and condensing water into it by closing it with a lid.

 

[Coolcasino]

What a tragic end to life... Atleast my probes and refractometer will be calibrated lol.

 

[Miami Reef]

@Randy Holmes-Farley @homer1475 @eag

I’m trying to calibrate the conductivity probe but it’s not working.

I put 1 Tsp iodized salt into 182mL of RODI water.

Randy’s article says that will make 53 mS/cm but the apex requires 53,000. I’m assuming that mS/cm = x 10^3?

Anyway, I put the auto temp correct to 2.2 and I floated my solution into my sump until the temps matched. I rinsed the conductivity in RODI and then dried it out. I then calibrated it and as soon as I finished it read 34.9

But then I took the probe out and put in the DIY calibration (shaking the air out) and it’s reading 38-39

What gives?

 

[Randy Holmes-Farley Verified Community Expert]

It’s best to weigh the ingredients rather than go by volume.

53,000 uS/cm = 53 mS/cm

34.9 is ppt? Or mS/cm?

 

[Miami Reef]

It’s best to weigh the ingredients rather than go by volume.

53,000 uS/cm = 53 mS/cm

34.9 is ppt? Or mS/cm?

I can weight the salt, but can I use my graduated cylinder to measure the liquid? My scale only goes up to 20g (it’s a calibrated mg scale). I have a different food scale, but I’m not sure how accurate it is.

I have no idea if the salinity reading is in ppt or in mS/cm. I will call them now.

 

[Miami Reef]

I can weight the salt, but can I use my graduated cylinder to measure the liquid? My scale only goes up to 20g (it’s a calibrated mg scale). I have a different food scale, but I’m not sure how accurate it is.

I have no idea if the salinity reading is in ppt or in mS/cm. I will call them now.

It’s in ppt

 

[Randy Holmes-Farley Verified Community Expert]

The standard is a 35 ppt/53 mS/cm standard.

How did you "calibrate" the APEX?

 

[Miami Reef]

I’m so fricking frustrated. I just put Randy’s recipe in my refractometer and it’s reading 1.000

It’s like just RODI water? Is this why my apex conductivity is so messed up?