Silent filters
For the 200 gallon tank, invest in an Eheim filter, or 2. I have the 2126, it is totally silent. At 6 pm one of the lights in my planted tank goes off, and with it the fan goes off. The tank is totally silent then -- so peaceful.
I do believe in double filtration, especially for large tanks.
I have read that the bacteria will begin to die off within the first hour of filter flow ceasing. I know that when moving a filter, one ought to lay the filter media in shallow tank water, just covering the media, to keep the oxygen up. And when power is out, one ought to open the canister to get air to the media. It really is important.
You have to remember, the filter bacteria are living creatures in your tank.