I say just clean your tank and do a 20% water change.....hey, water changes are always a good idea....algae might not hurt....neither, is a clean as well.
it won't hurt the aro, but you shouldn't have too much of it.. plecs usually don't suck slime off of fish that move a lot, like dats and aros. if you want a cool fish that eats algae, get a flagtail. of course, there are a lot of cool plecs, but they don't eat that much algae, esp as they age