actually i would use algaecides last and the UV
filter before that. Try a blackout and see what happens. I read that algae problems arise from excess nutrients in an aquarium, which isnt a bad thing but lets algae thrive when plants arent around to suck up the nutrients. And the common pleco and rubberlip will eat solid algae...however pea soup is microparticles of algae (its simplest form essentially) and for fish to eat it they would have to drink massive amounts of water to consume it since the particles are so small.