The skimmer weir is the gatekeeper of your pool's surface.

It’s a floating flap inside the skimmer that regulates water flow and traps debris. Without it, leaves float right back out.

The weir creates a small waterfall effect, pulling surface water (and everything floating on it) into the skimmer basket. When the pump turns off, the flap closes, so debris stays trapped inside instead of drifting back into the pool.

You can usually adjust the weir’s tension or replace it if it’s cracked. Broken weir = worse skimming. Pretty simple.