Works fine for me.It is aptasia..a pest anemone.They quickly multiply,and can overrun your tank.There are many ways to get rid of them,including a shot of kalkwasser paste.Take a syringe,some thick kalkwasser..and carefully "feed' it to it.If you go at it slowly,it will actually think the kalk is food,and try to ingest it.Once you have it coated,it should die in a day or so,although sometimes they need to be dosed again.