'Zoe' Vitamin Suppliment dosing

So i have a tang that is starting to get HLLE and so i read nutrition is GENERALLY the number one cause, so i figured she wasn't getting enough vitys and stuff and went out and bought Zoe. So i am trying to figure out how many times a week i should feed with Zoe, i noticed the tang is slightly somewhat better from the dosing of the vitys in the food; however, now the clownfish has a wierd greenish tint/hue to it's top white stripe coloring. I have fed the vitamins back to back 2 days in a row (apparently bad idea), i think i may do it twice a week. Anyone know why the clownfish has a greenish tint to it's white top fin? Or suggestions on how often to feed this vitamin stuff?

Alternate between the Zoe and Selcon.  Both are good and provide different stuff.  Be careful though, a little Selcon goes a long way and you can easily polute your tank with it.  I would use Zoe and/or Garlic Guard to soak dried seaweed with.