Sometimes, our rocks and sand can become covered with diatoms, cyanobacteria, and dinoflagellates…often ruining the overall look of the aquarium and causing the entire thing to be one giant eyesore. Because of this, many hobbyists resort to manually removing these substances through various means. A common approach is to blow the stuff off the rocks and into the water column, where it can be sucked into filters and protein skimmers. While this approach has the most immediate impact of removing the unwanted organisms from the rocks and sand, it can also create havoc in the aquarium. The tank can instantly become cloudy with brown and dark purple gunk, and all of the commotion can stress out fish and invertebrates, and even cause corals to slime up. These situations can also lead some aquarium equipment to stop working properly, or even at all as things clog up with random debris. So, when blasting the rocks, be sure to take it slow and not let your frustrations get the better of you. Do one small area at a time, and move methodically through the tank. Just keep in mind though, that the stuff may come back unless the problems causing them are removed first.