Remember that these are theoretical concerns; and often a theory is just that, a theory. Reality is often times different. As an example, let's assume that you want to build the most efficient skimmer for a 100 gal-reef tank. Using the skimming laws above, the skimmer should have a five to six foot tall, eight inches wide reaction column, with a turnover of two tank volumes/day. It would have dense thick foam consisting of 0.2 to 0.5mm bubbles, injected in a counter current fashion against the water entry. So, while this might be the most efficient skimmer, it is also, in my opinion, impractical for many hobbyists. This is where we can put aside the theory as directly written and understand some real world examples.