draining the pond will work a local lake "somerset lake" used to be drained every few years to kill the algae but if i was you id rake the dried stuff up so it doesn't come back so quick. but you dont want to drain all the water just leave a few feet of it to keep the fish alive also with that kind of spring flow youl need to use a siphon to drain the pond and keep it low.

Sarcasm...yet another free service I offer.