hair algae thrives on high oxygen i think. I have quite a tall 30g so i need to pump oxygen for some dwarf cichlids at the bottom, but the hair algae just devestates all around where the bubbles are breaking the surface. ive got this plant that helps out compete it a little and it has thin leaves and grows like a mother f,, ill try to find the name, its like purple'green, with needle leaves. my 2 cents. i bloody hate that algae though, hate it.
i found this online havent tried it but will: Barley emits a certain type of enzymes that suppresses the growth of string algae. You can for instance use barley bales or barley extract. Since it only suppresses the growth of string algae, barley will never remove existing algae from the pond or aquarium. Don’t loose heart if it takes some time for the barley to start showing results; it can take several weeks before the enzymes have been thoroughly distributed to the entire pond or aquarium. You can increase the speed by placing barley in parts of the pond or aquarium where the current is strong.