Keep debris out of rain barrels

All of my rain barrels that are directly under down spouts have screens to keep out debris. 

The screen on the barrel keeps out the larger debris.

So I was quite surprised when I looked inside one the other day and saw this.

Closeup picture of the debris that go through the screen, but not into the barrel.

What a mess.  I don't need that stuff getting into my drip irrigation lines.  There's a chance that it already has.  Anyway, the question now is, "What do I do about it?"  I figured that I had two options.  I could build some first flush diverters that would hopefully catch and divert the smaller debris away from the barrel before it started to fill.  Or I could get a tighter screen to stop the smaller debris from entering the barrel.  I really liked the idea of the first flush system.  It's probably the more permanent long term option.  It's also more costly and time consuming to install.  So I went with option #2, the tighter screen.  I ordered some mosquito netting from Amazon.  Total cost was less than $9.

Installation was pretty simple.  I put the netting on top of the existing screen, screwed on the lid, and cut away the excess material.

As an added precaution I also added a screened washer to the hose attached to each barrel.  I'm hoping that it'll prevent junk from getting into the drip lines that connect the barrels.

New screened hose washer on the left.  Old normal hose washer on the right.

Screened hose washer installed.

I didn't check inside the barrels after the last rain storm, but it appeared as though the mosquito netting did catch a lot of tiny debris.