Flatworm Exit: Made in Holland, Treats 1200 liters, Reef Safe & Fast-Acting Flatworm eXit is safe for fish and invertebrates, but their body fluids can be toxic to other reef inhabitants. When using this product, follow these steps: 1. Remove as many flatworms as possible. 2. Have fresh activated carbon ready. 3. Turn off UV, ozone, and remove activated carbon. 4. Keep the skimmer running. To reduce the amount of toxic body fluids in the water, blow water into potential hiding places to flush out any remaining flatworms. Don't forget to siphon out any flatworms that are hiding. It's also important to remove any dead flatworms and use 1 pound of fresh high-quality carbon for every 50 gallons of water. Take your time when treating the tank and monitor it for at least 6 hours after treatment. Keep 25% of the water.