Wet-dry medium - suggestion

This is in response to inquiries recently about medium for DIY wet-dry
filters. My favorite is foam filters from Aquaclear (I've used several
types of plastic bio-balls, cubes, ribbons and sandwiched netting, as well as
ceramic cylinders, clam shells and lava rock).  Advantages are:

1. Efficient use of space - rectangular shape allows stacking.
2. Large surface area to volume ratio.
3. Good flow and distribution of water. Pores are large so clogging is not a
problem and water flows easily keeping the whole sponge wet.
4. Low cost.
5. Light weight.

I use the Aquaclear 300 foam blocks which are approximately 5.5" x 3.5 " x 2".
You can build rectangular cylinders (using plexiglass) in which several of these
blocks can be stacked. Very compact and light weight.

Shiao Y. Wang  
University of Southern Mississippi
sywang at whale_st.usm.edu