I love the stuff.
I generally pull some(a small amount) of my mash runnings, mix in my yeast nutrient when the runnings are hot, let that cool a bit and then add my SuperMoss, a 1/4 tsp per 5 gallon of finished beer. Mix that up and add it about 15-20 minutes left in the boil and begin to re-circ at that point as well. Clears things up well!