For my CSS 65, the pump pushes more water than air causing the foam head to rise and fill the collection cup so fast that some of the skimmate will flow back into the tank and the rest will go through that top hole, follow my cord to the drip loop and down to the floor. Its usually my fault though when it floods, because I havent cleaned the air intake of the skimmer so whenever it floods i know to clean the intake. One thing that helped it stay stable for me was to keep the output out of the water to reduce back pressure. But other than that it pulls out pretty nasty skimmate, and im pretty happy with it.
If you have a bucket underneath it should be okay but if it floods im pretty sure there it will flood more than usual because the skimmate will fill the bucket before getting on the floor, whichs leaves more time for flooding before you realize that it is flooding.
hope that helps.
