It could be a couple different ones. If its slimy, it's most likely Rhizoclonium. This is caused by low CO2 and nutrients along with the higher lighting.
It could also be Spirogyra or Hair algae. Both are caused by a possible increase in ammonia, Low CO2 and light.
The best thing to do is to do the opposite of what's causing it. Decrease light, increase CO2, increase nutrients (to an extent) and keep up with tank maintanince (water changes, gravel vac). Also the easiest way to help get rid of it is to take a toothbrush and basically wind the algae up in it.
It could also be Spirogyra or Hair algae. Both are caused by a possible increase in ammonia, Low CO2 and light.
The best thing to do is to do the opposite of what's causing it. Decrease light, increase CO2, increase nutrients (to an extent) and keep up with tank maintanince (water changes, gravel vac). Also the easiest way to help get rid of it is to take a toothbrush and basically wind the algae up in it.