precipitating sodium bicarb?

[sphelps]

Are you mixing it with the proper amount of water first, before adding to the tank? Then are you adding it slow enough?

I know something else in the water in needed to create the reaction needed, I'm no chemist so I'm not 100% sure what it is (could be CO2 or hydrogen ions??) but my guess is you don't have enough of it, whatever it is

I don't usually dose sodium bicarb but I do often dose calcium hydroxide and if I need to dose a lot I add vinegar as well which not only prevents the PH from spiking but aids in the reaction preventing precipitation.