The package says start with 1-2 tablets per serving, increasing to 10 tablets over time. 10 tablets is 2grams.
I think that is simply the weight of the tiny little 10 tablets.
I take about 10 daily with a meal and never noticed any unpleasant side effects. As a group we all varied the amount of cilantro in our smoothies, I don't know of any exact recommended medical dose, we are basically experimenting with ourselves.
Even though I stopped the cilantro smoothies on a daily basis I still take the chlorella/spirulina, it's so easy.