Looking for sump design help

[gregzz4]

To elaborate;
If the pads are 1" thick, make a section 2" x 18" F-Back.
Put a verticle glass partition F-B maybe 1/3 top down.
Water flows through your coarse pad (forced through by your 1/3 high baffle), then the fine pad, then up and over the next baffle.
Sure, some will sneak through the top of the coarse pad and over everything, but the heavy stuff will hit the bottom of the sump before it gets to the pads anyway.
And if you really are worried about it, add a F-B flat top over the coarse pad.
Then you would remove the fine pad vertically, slip the coarse one over to the fine side against the baffle, and pull it out vertically.