How big is your tank? What kind of filtration? How long has this tank been established? How often are you feeding? How often are you doing partial water changes?
I'm guessing that "power" was supposed to be "partial", but with nitrates that high, you need to do some water changes quick and try to figure out where those levels are coming from (thus all the questions above).
I'm hoping this is not a case of putting too many fish,too quickly, into too small of a tank. Bio load deals with the amount of waste your fish are putting into your tank. If they are putting out more than your beneficial bacteria can handle, your parameters will become bad, causing bad living conditions for your fish.
There are a variety of threads on treating Ich on this site (and others). Garlic helps boost immunity, but does not cure anything.