Leo, a quick search on e-bay showed Betaine anhydrous, Reagent 98%, 100g $44.99 in Japan.
Is there a more economical source in the States?
Is 2g per 1/2 tsp about right?
Esshup, careful about buying anhydrous betaine off ebay. You may get a load of caffeine that looks like betaine, which can be detrimental to the fishes.
As for the reagent at 98%, of 100g at $45, you're talking about the 5M concentration at purity. Pretty strong stuff. You only need less than 0.5g to initiate a massive response. You only need the common 2M concentration, which cost about $10 to $15 per 100g. Another name for the compound you can find is called trimethylglycine. That may bring up a better deal for you.
As for teaspoon to gram, it's roughly 4.6g to 5.3g to 1tspn, based on density of the material you're measuring. So, yes..about 2g is about there for the basic 2M concentration of betaine.
