Flatworm Exit

Flatworm eXit itself is quite safe to fish and invertebrates. However, the body juice of flatworms can be toxic to some reef inhabitants when present in a too high concentration. This body juice is sometimes excreted when flatworms die.

So when you use this product it is important to do the following first:
Siphon out as many flatworms as possible.
Keep sufficient fresh activated carbon in a canister ready.
Turn off UV, ozone and remove activated carbon. Keep the skimmer turned on.