I'm in the process of installing a fair-sized pool, stream and waterfall. The land has a natural gentle 30' slope that we followed with the liner and stones, terminating in a 8' round and 2.5' deep pool. I started with a 1450 gph pump with a 1" line but upgraded to a 2900 gph for more flow. The problem is I can't get the water to actually FALL off a rock- it goes under, around and thru but not over. What am I doing wrong?