I used nothing from the orca dart.
The hammerhead comes with a cnc machined needle wheel.
I used all new plumbing fittings from the unions out on each side of the pump, that way I still have the dart needle wheel and plumbing as a back up.
I no longer need the air pump and actually have to throtle the air intake back some in order to skim without the larger bubbles , its working great and im glad I have this skimmer.
I dont think it needs mesh on the cnc needle wheel ,also think it might be difficult to get it to suction right with the mesh and it might be hard to keep the mesh on.