Cleaning your tank during a showing of ICH

I recently had a Hippo Tang showing a few dots of ich verry mild but still concerning. I have never had ICH in the tank and am lost as to how it got there as we quarentine all incoming fish. (maybe the parasite hichiked on a coral or snail shell during is reproduction stage?)

problem number 1 is I have a 180 reef with tonnes of rock, catching one fish never mind all of them is impossible without ripping apart the entire tank. I would love to quarantine all the fish but this is a complete last resort. moving 250+ lbs of rock and coral is not my favorte past time.

I talked to I think every salt LFS in the entire city and all of them have these Miracle cures (medic, Kick Ich, ich x) I am not sayng they wont help but has anyone had success with these? have they had any effect on coral even though they say their reef safe.

Finally I had one store tell me that I should be doing 20% water changes every two day and cleaning the tank before each change, while another store told me not to clean the tank for fear of stiring up the reproducting ich, and just allow them to stay dorment and not attach to any fish so they can die off.

Should I be Cleaning the tanks? should I be doing large frequent water changes? should I look at trying a Miracle cure? any suggestions would be appreciated?