Alkalinity reference solution?

[tmccaff]

I am using a KH carer and wanted to use a reference solution to figure out if it’s accurate. What can you use? Can you use GHL kh director reference fluid? Will any reference fluid work? Thanks

 

[tbrown]

You just need to make a known solution and test it. RODI mixed with a carefully measured portion of baking soda would work. Or, any of the commercially available reference fluids or even a alkalinity supplement. As long as you know the solution strength, you can use it.

 

[Randy Holmes-Farley]

This has recipes:

DIY alkalinity standard

For folks who may want to evaluate the accuracy of their alkalinity test kits, here are two suggested ways to do it. One is DIY and one is a mostly commercial standard with one DIY step. Method 1 Standard solutions could be made with sodium bicarbonate, but it can be hard to be sure it hasn't...

www.reef2reef.com

 

[tmccaff]

@Randy Holmes-Farley so the stock solution #1 you take out is 15.1 ml to 1 litter of rodi correct?

 

[Randy Holmes-Farley]

@Randy Holmes-Farley so the stock solution #1 you take out is 15.1 ml to 1 litter of rodi correct?

To 1 liter final volume, not 15 + 1 L. :)

 

[tmccaff]

Ok, I made 1 litter of rodi and added 10g of baking soda which made solution one.

Added 15.1g to 1 liter bottle added rodi water till it read 1ml.

Tested with salifert test kit and it read 10.2 either I did something wrong or this test kit bad

 

[Randy Holmes-Farley]

Ok, I made 1 litter of rodi and added 10g of baking soda which made solution one.

Added 15.1g to 1 liter bottle added rodi water till it read 1ml.

Tested with salifert test kit and it read 10.2 either I did something wrong or this test kit bad

Well, couple of things. The recipe is sodium carbonate. Did you bake the baking soda to make sodium carbonate from the sodium bicarbonate?

Regardless, not baking would give low alk, not high. Literally following what you did should give alk of 5 dKH.

Are you sure you are reading the Salifert syringe correctly? Many folks read it backwards.

 

[tmccaff]

Yes baked it. I will do another test