How do you slow down a pump? I do have a ball valve on just past my
pump before my filter. The PVS is split into a "Y" with one side
going to a waterfall, the other going directly to the a return back to
the pond. (I plan on adding a veggie filter next year)

The water fall has vinyl tubing from the pump, the rest of my plumbing
is PVC. Can someone tell me what I need to do. (I can post some pics if
that wold help too)

Thank you