I have a 10 gallon porcelain bowl set up that receives very little light. Until recently, the only plants were a couple of anubias. About six months ago I noticed the sudden appearance of what to me looked like brown algae around the surface of the bowl. The funny thing it seemed to favor one side of the bowl over the other so I imagined it had something to do with the amount of natural sunlight that hit the bowl. Research revealed that brown algae isn't really algae at all but a single-celled organism that establishes itself in colonies to anything containing silica, which of course, is contained in porcelain. But, now I am learning that beneficial bacteria also cling to the surface of ornaments and similar things in an aquatic environment. The fish don't seem to be bothered by it at all, but it does make the tank appear "dirty". So I wiped it away. Was that a mistake?