You vodka guys, it soo complicated I can't even get through it in my head. LOL
I think a restart is his best bet and lieu of that, doing what I normally don't recommend, adding alage eating creatures.
A picture would help alot, if it's a literal field of alage I might think those creatures would mow it down in a week or so and you can see what you've got growing underneath and make a decision then. Just make sure that the lfs
will take back whatever you buy if its not snails or hermits.
I'm thinking a seahare and hermits larger ones,some emerald crabs, some turbo snails, a good amount and some asttraa snails. The seahare could easily run out of food so I'd be careful with him if you kept him. I've had mine for about 8 months and he is an eating machine. I feed him alage sheets now since I have no algae. A lawnmower blenny would also be awesome in this application adn is a fish you'd wanna keep anyway.