how long to leave a tank fallow

[marineman41]

I have a 187 gallon aquarium.
It has been up and running for a little over 4 months.
About a month ago I came home from work and proceeded to head down and feed my fish.
When I got downstairs my water was all cloudy and when I lifted the canopy all the pellet food from my auto feeder was floating ontop of the water or in the water column.
I grabbed a filter sock at skimmed the top of the water with it and did a 20 gallon water change.
My fish were all at the top of the water breathing rapidly.
I transferred all the fish (5 in total) to my 33 gallon cycled QT tank and continued to do 20 gallon water changes every other day.
I purchased a UV sterilizer as well and that cleared the water up within 2 days.
While in QT all fish developed ich the next day from being transferred from the main tank.
I tried to get the fish to begin eating again before I medicated but it was too late. I lost my last fish 1 week ago today.
The water in my main tank is all bad to normal.

How long should I wait to add fish back into the main tank. I am sure ich is in the main tank and don't want to rush.
I have read, on reefcentral, to let the tank go fallow for a of 8 weeks.
I wanted to buy a 1 or 2 fish this week and put them into QT.
Its hard staring at an empty tank when I initially waited 2 months to add fish!

Guess I am just venting.

Let me know what you experts did if you have went through this before.

Thanks for looking!