Hair Algae is very common in salt water and reef aquaria.  As detritus builds up in the gravel, rock, and corals it forms perfect little "planting beds" for these evolved microalgae strings.  As they photosynthesize oxygen bubbles get trapped and sheets of green hair mats float to the surface.   Once this happens the aquarium produces a foul odor that can only be described as a port-a-potty at a Grateful Dead concert.  By simply siphoning the trapped detritus during water changes will remove and prevent this from ever happening again.

Red-Slime Algae is very similar to hair algae being it can also be caused by excess detritus build up.  But red-slime is more than just a plant. It's actually a  bacteria laden algae called Cyanobacteria and is considered one of the oldest forms of life on the planet.  Once you get red-slime you may find it difficult to get rid of.  Weekly water changes and siphoning the slime off will eventually rid your tank of this menace.  There are products out there that will rid your tank of red-slime in a day but be sure to perform water changes before and after using these antibiotics regardless of what the directions say.

Not all red and green algae's are undesirable.  In this photo red macro algae grows like a little shrub in a well established reef tank.  Looking at the right of the base you'll notice a green macro algae.  Some people love this stuff, others hate it.  Personally I think it looks great but if you don't feel the same way simply pluck it off and throw it away.  These algae's usually grow slowly in low current areas of reef aquaria.  If your tank is over run with macro algae it's safe to say that you need better maintenance and more current.

I'll be adding a lot more to this page as I get photos.  Until then check out Support for other common problems.  Any questions just e-mail me and I'll do my best to help.
david@kissyourfish.com