The rain barrel filter works!

I installed an overflow rain barrel under my deck the other day.  I put a filter on the input tubing in the hopes of keeping pollen out.  I checked the filter once the barrel was full.  I was surprised to see how dirty it was. 

I removed the filter, washed it off in the sink, and re-installed it.  It's good to go for next time. 

I can see how much dirt it kept out, but I wonder how much dirt it let through.