Simply, it's 120mg of NaHCO3 in 1L will yield you 4dKH (4.0052).
So everything change will be in proportion to that.
so in 500ml, you'll need 60mg of NaHCO3.
or if you need a 40dKH solution, just multiply 10 to the amount. in 1L of water, you'll need 1200mg or 1.2g of NaHCO3.
Oh, on converting carbonate/bicarbonate use the proportion as stated in the article, .71423/1.4285
Last edited by mistergreen; 11-05-2014 at 03:58 PM.