From you pictures I'm not sure your "hair algae" is that at all. It appears to be bryopsis.
You've had your biopellets on for about 2 weeks now? I'm not sure you would be seeing results that fast in a "stop in algae" growth. Pellets are well known to reduce nitrates a whole lot better than p04, so I'm not sure you should be using them with anything other than the carbon source that they are.
They are not a one stop n03/p04 shop.
You appear to have cyano as well. I would work on getting those in control before worrying about colors or anything else.