Get SeaChem's phosphate kit...its the best one available. If the 'hair' algae is several inches long, it's thread algae, often caused by too much iron. if it's short and dark, it sounds like black beard algae, and in my opinion means your nitrates are too low compared to the phosphate level. should be a 10:1 ration, so if phosphates are 1ppm, Nitrates should be at least 10. If you wanna keep stuff red, keep nitrates lower and once you get your phosphate test kit, keep it lower too, like .5ppm.