One of my 20g's has recently exploded with hair algae and cyano. I added a protein skimmer and new light (probably the problem) about a month ago. I used to have 2 18 watt lights, now I have a 65 watt PC. This must be the reason for the intrusion, as my water parameters are the same as they have been for months.
Anyways, I have about 1/2 dozen hermits and 2 astraea snails which aren't doing anything to fight the algae. Recently I added an emerald crab and 2 Mexican turbo/ grazers. The large snails are doing all they can, and have made a dent in the algae. I think that with time, water changes, and a good cleanup crew that the algae will go away. My LFS has had Rainfordi Gobies for the last few weeks and I am thinking about getting one of them to help with the hair algae, but I am scared that the Fridmani pseudo may bully it.
In another attempt to combat the algae I converted my Aquaclear 20 power filter into a mini fuge with a ball of chaetomorpha and light. I'm hoping that the macroalgae will outcompete the nuisance algae, along with the help of my inverts.
Good luck, and let me know if you find something that works well and I will do the same.