Quick update: I ran the pump without the cartridge and with a pollen cloth in the skimmer basket for 2 days while the cartridge soaked in cleaning solution. Within a few hours, I collected enough pollen to make a nice yellow "snowball". No wonder the filter clogged so fast! I put the cartridge back in and it's been running beautifully.
I want to thank everyone for spending the time to help me with this issue.
Eric