I have had my 20gal tank up for about a month now with no real issues that I know of. My water test come back with 0ppm on ammonia, Nitrite,and Nitrate today but I have what I am guessing is brown Algae. I set my tank up with tap water at first and did my first water change with RO/DI water last Wednesday and a new brand of salt. Today,brown spots everywhere, its on the rocks, crushed coral substrate and glass, some even floating on the surface of the water. I am unsure how to fix this.
