Algaecides are used to get rid of all types of algae. There is green, yellow, black and pink algae. While most of them will do the job, they will not get rid of the problem which is high phospahtes.  For that solution refer to  Phosphate Removers.  

Copper algaecide is mid range,  but  adds copper to your water and when combined with chlorine copper will turn your hair green.  We do not recommend copper algaecide.

Amonia algaecides are the cheapest but will cause foaming in your water. Do not use those in spas or in large quantities. We do not recommend amonia algaecide.

Poly Algaecides are the best for most algae problems but tend be more expensive.   We recommend poly algaecides and the 60% poly is the best and the 30% or less if for maintence only.

Then there are special algaecides for black, or pink algae. Silver algaecide is the best for pink algae.

NOTE:  Always have your water tested for phosphates if you ever get algae.  Treat the problem and maintain with algaecides.