Molar concentration of HCO3-

What is the molar concentration of HCO3- equal to 4kH?

Ive looked at some different explainations, but ive found no clear answer, and it confuses me...

There was a scheme with recalculations of kH somewhere...

4 kH = 0,0744g/L (You forgot to calculate mg to g)

So 4kH equals 0,001171147M of NaHCO3, and if i wanted to test my kH 4 solution...

I would titer my kH 4 solution with a 0,1000M HCl, and i should use 11,71mL HCl/L right?

But if i wanted to make a 4,00 kH solution, i need som accuracy.

Im making a batch with 0,2495g of dried NaHCO3 (200ºC for 45min) dissolved in 2,0 L MQ water.

That should give me roughly a kH 4 solution.

Then i would just titer it with HCl to find the exact concentration, and adjust it with more MQ water/NaHCO3.

Or is there an easier method to make kH 4,00 without a standard solution.

I got all the lab equipment possible (well almost)

If you got an easier method im all ears.

So what is the recipe for a 4,00 kH solution using sodiumcarbonate?