this is how clean up crews including fish work:
most of the time you add them, they contribute to tank waste loading which begets more algae, and they dont touch the target. sometimes you add them, their waste loading is worth the algae work they do, this happens 5% of the time
large tanks are more dependent on animals to hopefully keep things clean, the tank is so big they dont have many direct control options. but smaller tanks, it'd be just as easy to drain the water out 90% and catch in a plastic tub, leaving the algae stuck to the walls, when water is removed use paper towel wet with peroxide to wipe up on the walls and simply physically remove the algae, refill, and be done with it and buy nothing and delay never. you have this range of control options.
its a harmless way of cleaning off glass algae with no water contact, nano reefers do this routinely as needed in many threads.
when you see reef tanks of any size that are overtaken with X invasion, they're opting to depend on external sources and new additions for their gardening (and those sources clearly aren't working)
nano reefs that are constantly uninvaded have caused that condition by hand usually, they did not depend on animals. a few got lucky, stocked some animals, and never had to work at all.
you will find simple direct control easier in the beginning before its all stocked up then over time maybe, if lucky, some animals will show promise.
