Treat 300 gallons. Chemi Clean will effectively remove many different strains that can be formed by cyanobacteria (red slime). It is common to encounter a red slime or matting algae that can quickly smother your rocks and even corals which can lead unpleasing aesthetics but also can cause issues with low oxygen levels available for fish and corals. The quickest and safest way to remove red slime from a fresh or saltwater aquarium is with Chemi Clean. For the best results, turn off or remove any carbon filtration source, UV sterilizers, protein skimmers, and ozone before administering Chemi Clean to the aquarium. After treatment is complete perform a 20% water change, after that point any carbon filtration, UV, protein skimmers*, or ozone may be turned back on.*It is very common for protein skimmers to over skim for a period of time after treatment is complete and is completely normal. We suggest monitoring the skimmer cup and removing any collected skimmate from the aquarium and not letting it drain back into your aquarium. If your skimmer is overflowing too fast, you can try restricting the air supply feeding the skimmer and that will decrease the amount of bubbles being formed or simply physically raising the skimmer body will allow for a faster drain and a dryer skimmate to be produced. Replace any removed water with freshly mixed saltwater. Chemi Clean will remove and clean stains from red, black, blue-green, and methane producing cyanobacteria in marine aquariums.