Aluminum sulfate reduces P in water column and in seals the sediment by binding to P and forming a precipitated material called ÔflocÕ that settles on the bottom.  This makes the P unavailable for algal blooms.
	Very effective for internal loading, which is the largest contributor of P in Togus Pond.  Alum is usually applied in concentrated liquid form, which is scattered from the back of a small boat, as you see here.