hey everyone, i know its algae, but my question is where is it coming from? my parameters seem ok, my skimmer is skimming like a champ, yet every 4 or 5 days i get huge amounts of build up on my glass and sand. its green and red and very unsightly. I have to clean it with a magnet to clear it but it just keeps coming back. any idea what kind it is and how to treat it? will it go away on its own? or just worsen? i wanna do a 50% water change now out of fear its due to something in the water....someone please help!