Cyano and algae problems?

[drillsar]

I have a 55gal tank with a mag 7 for my return, I have mostly the Cyano in the back of tank and brownish algae on one side of my tank.

Phosphate 0
Nitrate 20ppm I know thats high trying my darnest to get this down Im thinking i need more live rock.

I do weekly water changes 15gal, Do i need more flow maybe? I have my return pointed to the center of the glass should i possibly redirect flow?

 

[Brenden]

Have you checked the PO4 level in your new SW?

 

[drillsar]

MY PO4 is 0

 

[Brenden]

Just wanted to clarify. 0 is new water and not from tank. I had a problem about a month ago. PO4 was 0 in tank even after WC but new water was .25. The cyano/algae was removing the po4 so it tested 0. New RO/DI filters corrected the problem.

 

[drillsar]

I have put in a phosphate reactor 3 days ago My phosphates where high now 0, I will look into that though..