If this helps any, I heard a long time ago that with the right conditions, if you have sufficient light, you get green water, otherwise you get a bacterial bloom. The point is both are driven by too much dissolved organics, with perhaps some other reasons.
So, if it were me, I would vacuum the tank, look for dead fish and leaves, perhaps clean the filter if it needs cleaning, and generally try to get rid of sources of food. The green water will subside by itself once the population gets big enough to use up the food supply. It is a single-celled algae bloom, similar in function to a bacterial bloom.