Make my own reference solution - kh / CA

[Dimorb]

Hello everybody.

I need to know how to make my own reference solutions.

One to control / test kH and another to control and test Ca.

I make my own for PO4 and NO3 and they work really.

I do have a Mastertronic for auto-testing and I've tried to use ATI ref solution and GHL ref solution but the test values comes back to high or to low. ATI doesnt offer insight in offsets so no way to know if 8,0 is "great enough" when the ref solutions says 7,5 is the answer.

GHL has to big offset - +/- 0,2 makes it impossible to use as a good control.

So please, if someone has a formula for "how to make your own" - kh and ca solution please post it...

Best regards

Andre

 

[taricha]

See this for alk.

https://www.reef2reef.com/threads/diy-alkalinity-standard.714738/

 

[Randy Holmes-Farley Verified Community Expert]

Hello everybody.

I need to know how to make my own reference solutions.

One to control / test kH and another to control and test Ca.

I make my own for PO4 and NO3 and they work really.

I do have a Mastertronic for auto-testing and I've tried to use ATI ref solution and GHL ref solution but the test values comes back to high or to low. ATI doesnt offer insight in offsets so no way to know if 8,0 is "great enough" when the ref solutions says 7,5 is the answer.

GHL has to big offset - +/- 0,2 makes it impossible to use as a good control.

So please, if someone has a formula for "how to make your own" - kh and ca solution please post it...

Best regards

Andre

A calcium standard might be asked to do multiple things, and how to make one is not especially easy.

One wants it to have a known level of calcium, which necessitates starting with a material of exactly known calcium composition, which is not trivial as they will generally contain moisture which either must be removed first, or measured.

Second though, is that one wants to be sure the kit is properly distinguishing calcium from ions with similar chemistry, notably magnesium. If magnesium is not in the standard, one is not fully evaluating the kit.

Both of these together make developing a calcium standard as not a simple DIY like the other standards might be.