The first treatment killed about 50% of the population. I am dosing the tank again tonight. This time I took my canister filter out (it has carbon in it... maybe why it didn't work fully!). I am just running the powerhead now. As a result of the first treatment my ricordia mushroom is not too happy ... he closed tighter than I ever seem him. I also a flowerpot coral ... not sure of the name, it looks like a snowball. Most of the little flowers are inside it which I haven't seem it do that yet. I have another flower pot that's green with long tentacles... that's the one that was mostly suffering from the infestation, he was covered with the worms. This second treatment I turned off the light. The instructions said something about UV and wasn't sure what the was about. I figured in a 4-5 hours I would do a water change. What is a fresh water dip???