I'm setting up the 5ft waterfall for it's location in the wall and it's flow rates with the pump. But here's my problem. If I have the returns running at the least amount the actuator will allow the valve to close i have to ramp up the pump from 65-70% to 80-90% otherwise I don't get enough flow on the water fall. Is it ok for me to totally shut down the returns whilst running the water fall. I was warned by the pool cleaner guy not to do this as it's will put the pool out of balance quickly and stuff will build up in the return pipes. The waterfall will likely only be running a few times a month and no longer than a few hours at a time due to the cost of running it at them RPM's. So is it ok for me to shut them returns down whilst using the waterfall?