HELP! One of my powerheads stopped

[RondaGP]

I just did a water change and vacuumm of substrate (coarse crushed coral).

I have an undergravel filter for a FOWLR (very little LR).

Now my left powerhead won't work.
I'm not sure the right one is working as good as it used to either?

I couldn't have clogged the tray up to point that no water at all will go throught it right?

[grimlock3000]

The impeller is usually just hung if this happens. Clean out the powerhead and try again.