My tank seems to have 2 kinds of algae, the first kind is like spots on plant leaves that don't come off easily. THe second is a thick coat of algae that is on some gravel, chain sword and my anubias. This algae will siphon off easily, but it always seems to come back. I have a 29 gallon tank with 3 small fish, plants, DIY CO2 (although I don't think it is working that well), 60 watts of light, weekly 20% water changes, and virtually no supplements except Floursih Root tabs once every couple of months. How do I get rid of the algae (and I do plan to get otto's, but they won't be enough)?