Yes, so that top put of the waterfall is actually about 6’ deep with rock and gravel filled all the way to about 6” below waters surface. Large rock on bottom to smaller rock on top. I have a 9000 gallon an hr pump on the other side of the pond about 4’ deep that pumps the water to the bottom of that pit and then cascades down a 3 tier waterfall. I also have a fountain in the center with a 3600gph pump. Both the bog and the fountain run 24/7 for the most part. My whole issue is water clarity effecting plant growth which is the reason for the algicide. I cleared the water about 2 months ago with alum, but then when trying to control run off by growing grass on the banks i inadvertently fertilized the pond and cause an algae bloom that killed all my Lilly pads and took visibility down to around 2” again.