Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Good to rinse the biomedia, just not with high chlorine water. Used tank water is better. The bacteria are well attached, and the rinsing just dislodges any debris, not the bacteria.
After activated carbon has been in the filter for even a short while beneficial, nitrifying bacteria grow on it. However, nitrifying bacteria do not grow fast enough to cloud the water, even if you removed the carbon and it had a lot on there. You might see a minor spike in ammonia or nitrite, but not cloudy water.
Heterotrophic bacteria grow faster and may cloud the water. But this sort of bacteria are usually seen in a new set up. They are present in all tanks, but are in balance with their food supply, so do not grow so fast as to cause cloudy water unless there is a major change in their food supply.