Algae inhibit other algae

My daphnia container crashed and I'm waiting for green water to appear like usual but instead some species BGA took hold all over the surface of the container. I fed the daphnia spirulina, maybe it's spirulina?

Anyway, with the BGA taking over no green water at all for a month. There was a lone large ramshorn snail in the tub. I added more snails and their population boomed by eating the BGA. With BGA reduced and greenwater is back. Hopefully, the daphnia will follow.