Powdered formulations can be broadcast, since they are highly water soluble and do not sink to become tied up in bottom muds. Build the platform so it can be raised or lowered. Lay the required number of sacks of fertilizer on the platforms so 4 inches of water will cover them. Tear off the top layer of each sack. Wave action will distribute the fertilizer throughout each pond.
Platform construction can be difficult in existing ponds.
An alternative method is simply to place fertilizer bags in shallow water with the tops cut out. The bags serve to separate soil and fertilizer, and wave action will dissolve and distribute the fertilizer. Dilute liquid fertilizer with at least two parts water to one part fertilizer before application. In small ponds, liquids can be sprayed effectively from the bank with hand-held sprayers. Boats make application easy in larger ponds.