If you're using outside air, you shouldn't need the scrubber.
If you're using outside air, and you are using the scrubber, then you don't need to recirc.
I think you recric when you don't have access to outside air, like myself. So my scrubber is fed off the top of the skimmer.
Also, you don't need an air pump for your skimmer. You just need to run the air line outside or to your scrubber.