So I have had some black beard algae problems and I have trying to get rid of it for a while now but it continues to spread. I have high pressure co2 and high lighting. ph is 7.4, ammonia .25 ppm nitrite is 0 ppm and nitrate is 5 ppm. I turned down my light from 8 to 6 hours. I also put 6 Siamese algae eaters in the tank, but nothing seems to be getting better.