Rather than using algaecide potentially causing harm to plants, animals, producing workers and the rest of the world
- Lower PO_4 value to the minimum by adding pug to the filter. Usually takes effect (with 1 mg/l) after 48 hours. It's the initial nurition for the algae.
- Provide less food which increases the PO_4 value (frozen food and others).
- Turn on an oxigen pump if you have one since O_2 production of plants is lower because of less light getting through.
- Move the aquarium away from direct sunlight impact (see How to move an aquarium? for things to consider)
- Keep a group of Daphnia (more than 5 make sense) in a container with a separation/membran which allows water exchange and prevents fish from eating the Daphnia as well as them to get out into the aquarium (where they'd be eaten). Ideally the separation makes the Daphnia invisible for the aquarium inhabitants in order to not provide them moving food all the time. Place the container with the separation into a stream (of the filter entry or outlet or the air pump outlet). The stream is visible by the green algae swathes.
You can track the progress by checking how deep you can see into the aquarium day by day. The Daphnia should start to multiply by 4 every 2 to 5 days and 60 l are cleared after a week. Then decorate your Daphnia with orders and release them as living food.
Example glass with plastic kitchen sieve (since Daphnia can't fully control their movement changes that small Daphnia get past the sieve are small; Mollys don't show any interest in Daphnia):
