Randy's fourth article in a series on reef aquarium chemistry for beginners. In this article Randy focuses on issues surrounding chemicals that build up in reef aquariums over time.

More... (http://reefkeeping.com/issues/2007-09/rhf/index.php)

Another good article (and series) by Randy Holmes-Farley. The series has less chemistry in it than much of his writing so shouldn't intimidate most people.