Algae blooms when there is an influx of nutrients within the water as well as few other things. There are a few factors which all coincide that determine the volume and longevity of this frustrating intruder.
Excess supplements and food products in the water raise levels of Nitrates and Nitrites, in addition to contributing to ammonia spikes. Algae thrive in conditions we'd consider less than desired. And even when water parameters are within a healthy range, excess detritus (biological waste and decaying plant matter), along with left over foods (which rot) provide the elements algae feed off of. Making sure that you keep your feeding in check, resisting the urge to over-feed or feed too frequently, as well as keeping your parameters in good order will help to reduce this annoyance. Additionally, in warmer waters algae thrive, so consider lowering the temperature in your tank. Limiting light exposure is also another factor, as algae is photosythetic and relies heavilty on light for survival. If you are running lights 12+ hours a day, lower that down to 8-10 hours a day. If you don't have stony corals which demand high spectrum, extended amounts of lighting, stick closer to the 8 hour limit. During the night, moonlights are fine, but anything else should be shut off, and once again, if you don't have an assortment of high maintenance corals, shut off the moonlighting entirely.
Purchasing animals who consume algae as a staple food is great - but only if you have a continuous supply, as otherwise their health will falter in the long run and they will become difficult to support. It's always better to opt for proper environmental management, rather than supplementing with controls (Fish).
Removing hair algae of which has grown into long flowing clusters can be accomplished with a siphon. This would only serve to eliminate larger colonies, preventing an excess of distribution, but would not correct the root of the problem. Furthermore, make certain that you are cleaning and changing out your filters and media accordingly, as once they become saturated with wastes, they lose their filtering and purifying ability, and are essentially, recycling wastes back into the water column.
Let us know how things go over the next few weeks. Hope this helped some.