I run a 90 with a pair of Blue Jaw Triggers. Recently I traded a rick of Palys for two skunk clowns and a coral beauty that was supposed to be 4". Since then my male Trigger showed up with Ich. I cured him in QT. Bur after puttong him back both Triggers had it and the Coral Beauty. It might have been Velvet. It was hard to see it. So I cured them all in QT and put the Clowns in there too. I used my Vortex Diatom in the DT the entire time the fish were being treated. It is able to filter Ich and Velvet from the water. Not 100% but a high percentage. Enough that health fush can stay healthy. So wel'll see if it works.