When all of this started weeks ago (I guess were into month's ago now).

I bought a digital scale, calibration weights, graduated cylinders, volumetric flask and some pipettes.

Then I was ready to make my own KH standard but I ran into the same problem. All of the calculators gave different amounts of sodium bicarbonate to add and there were issues with heating the sodium bicarbonate and it changing to sodium carbonate.

I went searching the web and posting on some chemistry/ lab forums looking for answers.
I took a couple of weeks and a lot of questions asked but I did find the correct answers.

I was going to post what I had found out about making the KH reference solution but I just haven't had the time.
Later this morning or in the early afternoon I will post how to make the KH reference solution and I think it will clear everything up.

I also have 500ml bottles of 4 or 5 dKH standard for sale, if you don't want to go to all of the trouble of buying the equipment and making your own solution.

Bill