Thought I would post an update.

I still haven't figured out a way to put some sort of screen bag/trap in front of the main filter. So I'm still having to pull the top and scoop out Mesquite droppings (flowers, leaves, etc) every week or two.

However, my daughter announced her engagement and they want to have the wedding ceremony under the Mesquite tree. Normally I hate grass in the desert, but having the wedding on dusty dirt along combined with threat of wind (not at all uncommon) forced my hand. Now I have sprinklers in that small area along with grass (tall fescue mostly) growing there. Once that's established, and will be left high most of the time, I'm hoping it will trap much/most of the mess in the turf. Then using the bag with frequent mowing will hopefully give me a way to control the worst of it.