All the white and light green are floss type media (about 6" thick total) so that sifts the particles out before it hits the bio-balls I ran out of the white stuff that's why you see the black bio balls. This floss type stuff is almost like a Scotch Brite pad it's for pond filters.
It's divided into 3 sections my thoughts were to experiment with different layers. I have some finer floss that I plan to stick in next time I pull it out. The whole filter slides behind my tank against the wall,,, basically you can only see it from the sides and it is VERY quiet.
So far the water looks very good and my tests look decent too other than the PH and I'll check that maybe tomorrow again.
Yes it's a custom, my first time seriously working with acrylic and it didn't go too bad,
I did learn some things along the way,,, first is even if you think you have enough clamps you don't.
My last filter was a stack of Rubbermaid tubs with holes in the bottom each tub had a different layer and they fit snug in top of a 10 gallon tank for a sump. They stuck over the top about a foot but they fit in each other so it couldn't leak worked great for about 10 yrs so well in fact I really never had to clean it. If you are properly oversized things should maintain themselves.
See my post here
http://www.monsterfishkeepers.com/forums/showthread.php?p=3360910&posted=1#post3360910
I have built some BIG filters,,,, Ha Ha!!