That looks like a soluble powder, not a meal. If it is soluble powder, it will have higher concentration of available nutrient compounds.
I use a soluble seaweed powder called EasyWeed by Blue Planet. I don't amend the soil with it, just mix into nutrient mix at feed time. Just checked and the packaging days 1/8tsp/gal during veg and 1/4tsp/gal in flower. Does not have instructions for soil amendment.