I got into the hobbie about 6 months ago and i've found the learning curve to be extremely steep

The LFS convinced me that quarantining wasn't necessary. Well they were obviously wrong and i have a ich outbreak now. I"m setting up a quarantine tank and moving all my fish over and since i have a new sump and skimmer that i haven't even had a chance to put on yet and its only a FOWLR system right now because of this i'm just going to tear down the whole system and restart with new dry live rock (and set up a aquascape i actually like) while the fish are in quarantine.
My questions are...
When i break down the system i've heard of using vinegar or bleach, how much seems to be a wide array of answers though, any past experience out there?
Do i just clean with it or could i fill the tank with tap water full and let it run like that then clean it/rinse it?
Also while im making a thread i got a cheap 30 gallon for my quarantine but it came with a tetra whisper filter 20-30gallon, is that ok or should I get something bigger. There will be 8 smallish fish in there.