My media chamber is lower than the mechanical chamber so it waterfalls into the k1 and starts the churn. Airstone across the exit of the chamber pushes the k1 up and back toward the front, completing the cycle. The only time the media tries to get into another chamber is when I turn off the pump and the overflows drain back into the sump. This raises the overal chamber levels so they intermix. I use crosstich screen to keep the k1 from invading other chambers during water changes. Soon as pump is back on everything returns to normal.