Green Algea & Soft Brown Algea overgrowth!

[elinkuge]

The live rock in my 50 gallon reef tank used to be covered in the hard purple growth (which I understood was good to have), but has recently been growing a soft thick brownish/red algea as well as a light green algea. This has also grown all over the 3 powerheads I have as well. Any idea why this algea is growing so much all over the tank so quickly & how I can get rid of it & back to how it was? Thanks

[michealprater]

Sounds like it could be cyanobacteria, you may want to increase the flow in the tank and add some more actinic light. A good water change may also help out.