ALK Calibration Fluid?

[scytale]

Is there a DIY stock solution that I can use to gauge ALK?
(maybe using a measured amount of kalk powder or baking soda....)

I just got a (new) Salifert ALK test kit and the results are showing +2.1 dKH from my old Salifert kit!!
(so I'm to trying to make a "control" solution to see which kit is "right".....)

 

[Boomer]

I just went through this on RC chem forum.

A good check but not 100% aaccurate like a real std is to take a liter of RO/DI water and add 1 gram, which should give aorund 3.2 meq / l or lets say 3.1-3.3 meq/ l .

Then there is this from a old online chem course

1. Weigh out 1.9 g baking soda and add it to the 500-mL graduated cylinder.

2. Pour distilled water into the cylinder with the baking soda to the 500-mL mark.

3. Pour this baking soda solution into the 500-mL beaker, and stir it with a stirring rod to make sure all of the baking soda has dissolved.

4. Rinse the 500-mL graduated cylinder with distilled water. Measure 15 mL of baking soda solution with the 100-mL graduated cylinder and pour it into the clean 500-mL graduated cylinder.

5. Add distilled water to the solution in the 500-mL graduated cylinder to the 500-mL mark.

6. This solution is your standard and has an alkalinity of approximately 84 mg/L or 1.68 meq / l

So, doing the same for 3.8 grams of BS = 3.36 meq / l

 

[scytale]

Thanks Boomer!
(Right now My tank's water is testing at 9.0, 10.9 or 12.5 dKH--depending on which 1 (of 3) Salifert test kits I'm using!! :shock: )
Hopefully I can narrow down which kits is giving the accurate reading!