Sodium Hydrogen Carbonate as a PH & KH buffer

[crabbit]

Can i use laboratory grade Sodium Hydrogen Carbonate as a PH & KH buffer or do i need to do the oven thing, as you would sodium bi-carb?

 

[bertoni]

That depends on the lab grade, but that chemical is identical to baking soda. No need for baking it, but it might have some problematic contaminants.

 

[Boomer]

crabbit

When you bake Sodium Hydrogen Carbonate (NaHCO3) it "drives off" CO2 which changes it to Sodium Carbonate ( Na2CO3) giving a higher pH and Alk by vol.. 1 tsp of Sodium Carbonate = ~ 1.6 tsp of Sodium Hydrogen Carbonate / 50 gal / 1 meq/ l increase in Alk.

oop's, I forgot most that I have seen, as so called "lab" grade, are 99.5 % pure which is not a worry. And most of that 0.5 % is Chloride, Sulfate and Iron.

 

[crabbit]

If i were not to bake it might this suppress my PH, or can i expect to get the same increase of PH and KH but have to use more as a buffer?
Also once it has been baked can I store it in a air tight container for weeks and still have the same effects as if it was freshly baked?
Many thanks for your help Mark

 

[bertoni]

If the sodium bicarbonate is used without baking, it'll lower the pH very slightly (maybe 0.1 or so) when added. The pH will rise as aeration removes carbon dioxide from the tank. If the sodium bicarbonate is baked, it'll raise pH, perhaps a fair amount, until aeration adds carbon dioxide back into the tank. Depending on the tank's pH and aeration rate, the baked product might help a bit with pH, although many people find that only fresher air or a limewater drip helps much.