When your adding a clean up crew it's always a good idea to NOT get hermit crabs.
In many of the clean-up crew packs that are sold, you'll see hermits added or even Mythrax (Emerald Crabs). It's best to avoid the crabs altogether and replace them with some peppermint shrimps or even a coral banded shrimp. The crabs by nature are scavengers. After they've run out of enough bite size morsels they'll begin evacuating and killing your snails, slowly but surely. I've seen them attack snails two at a time (crabs) to eat them and then steal the shell which they usually dispose of in a few days.
The difference is the snails will actually eat up a lot of algae where as the crabs will eat little to none. Even the Emerald crabs are not particularly fond of bubble algae despite what you might read, yes they might eat or nibble at it but at the same time they don't last very long and normally find a better food source.
Your best mix for success of algae is plenty (and I do mean a lot) of snails, a few shrimps and of course a lawnmower blenny. Be sure to not have a Tang as the Tangs and the lawnmower blenny will be vying for the same food source which normally turns out to be disastrous (for the blenny).
For a particularly bad case of hair algae, simply remove what you can by hand and allow your critters to catch up to whats leftover. You may want to also check your lighting as the bulbs might need replacing. I've found this out that with a newer light source (bulbs) the hair type algaes don't seem to thrive very well unless the lights are close to spent. Not always mind you but more times than not it's true.
