I received my new impellars for the Sedra 5000 pumps on my CS12-2 skimmer.

Here are some pictures. The upgrade didn't take long at all. I simply switched out the current ones for the new ones. I also got a special drill bit to bore out the hole for each venturi. These before and after pictures may help you see what a difference it made.

Before, the bubbles are right even with the base of the collection cup.

After, the bubbles are ready to spill over (and did about 90 seconds later).

Before, the bubbles in the base.

After, the bubbles appear to be more in the base.

The impellars. Old on the left, new on the right. The newer one has taller needles.

New on the left, old on the right. The pins are configured a little differently now.

The drill bit.

Venturi drilled.

Before...

After...

Bubbles!

I had to dial the skimmer back to drop the water level in the skimmer's neck about 5" or so. An hour later, here it is.

This was a very easy upgrade, and according to Jeff at Euro-Reef I just doubled the Liters per minute of air pumping into my skimmer.