Yourt message reminded me that our pond has avoided green as well.
Our 4 x 4 veggie filter of water celery seems to have done the trick
for the whole pond. The UV has not been thought of...

The WC is thriving!

Our hyacinth are just sending out some new leaves. This winter was
pretty hard on them. Maybe 15 have made it through. The remainder of
the 4 x 16 surface of hyacinths died! That is a sad record.

Jim