For velvet or ich the treatment options are copper or hypo from what I have been researching. Each one seems to have their pros and cons. Which ever you pick remember to do water changes, check PH, copper if using it, and alk. Make sure to treat outside of the display tank. I still haven't decided which treatment method i'm going to do. Some people say hyposalinity, but if you don't monitor it correctly and keep it at the right range it's not effective. If you use copper you have to watch other parameters because they can make the copper very toxic.