Building a sump

Ok... now that I have tried my hand at working with Acrylic by building a small (2 gallon) tank, Im ready to start designing and building a sump. The basic plan is to build a sump that is similar to a Tidepool with the pull out trays in the bio tower. Instead of a biowheel like the Tidepool, Im planning on using 3 gallons of bioballs.

I want to have 4 trays in the bio tower.

1) Prefilter / drip tray
2) ?
3) ?
4) Bio Balls

This will give me the ability to place whatever I want in the 2 middle trays (Crushed coral, Carbon, etc).

Im planning on building the biotower as a stand alone unit, then building the sump itself, and placing the bio tower in it.


The way I see it, 1 gallon of bio balls came in a 9" x 5" x 6" box. That's 270 cubic inches... Times 3 thats 810 cubic inches for bio balls.

I want to have 5 inches of water under the bioballs. This will be the water level in the sump (should be enough to cover the submersible return pump).

Now...

The question is, whats the best way to construct the trays? I know the top one needs to be a drip plate 2 inches deep acrylic tray with holes drilled in it. What about the other trays? Should each one be another drip plate style or should I use egg crate for these?

The sump thread from the old board contains some useful information but... its mainly about overflows and plumbing rather than the actual issues one is confronted with when building a DIY sump and biotower.

My question is more geared towards building the actual filter and sump than overflows etc. If anyone has information regarding this, Id greatly appreciate it (See the first post in this thread).