Keep in mind that DD's designed the system so that the waterfall to the res falls thru a window screen. This allwas you to keep any roots or other crap out of the system. Its like a cheap filter :)
How about Easypleasie's sock filter on his drain outlet? I think that thing looks sweet! Looks like it might even filter out some sediment as well. I'm sure that finer filtration means more attention to prevent clogs, but it would seem worth it to me.
The paint strainer I use works great. Tip I got from JK. It's elastic and fits nicely around a 4" drain. And it does catch a lot of the sediment from the hydroton. Since I start using the sock in veg, it cleans most of the crap out by the time you're suppose to put them in the mpbs. Easy to take out and clean. They're only a few bucks so a good alternative to the screen.