Randy's new long awaited article is now out on how a skimmer works
http://reefkeeping.com/issues/2006-08/rhf/index.php
Table of Contents;
Why Export Organic Matter?
Basic Principles Involved in Skimming
Hydrophobicity and Hydrophilicity
Basic Skimming Function
The First Step: Air/Water Interfacial Area
How Much Absorbs at the Interface?
How to Generate Air/Water Interfacial Area
What Collects at Air/Water Interfaces, and Why?
Why does skimming work better in saltwater than in freshwater?
Are inorganics removed?
What else is removed?
What organics are not removed?
Allowing Time for Absorption
Foam Formation and Draining
Wet vs. Dry Skimming
Bubble Popping
Bubble Popping in Marine Aquaria
Collection of Drained Foam
Skimming and Ozone
Aeration by Skimmers
Extra Supplements when Skimming?
Skimming and Salinity
Conclusion
General References
Skimmer Engineering References