I has an experience where the bubbles get stuck in the middle of a double stacked cell. The top cell would get clogged at its intake(bottom) with bubbles and stop working right.
Well actually, What it does is, The amount of large bubbles will cut back, And the flow slows down. creating more tiny bubble. like a white foam. If I have this problem with my new cell, I'll put a pump inline, To maintain circulation.
Spike
