As defined by
http://en.wikipedia.org/wiki/Addiction :
"Addiction is an uncontrollable compulsion to repeat a behavior regardless of its negative consequences. A person who is addicted is sometimes called an addict."
I must be at the plateau of my addiction, since I no longer seek bigger and better tanks, more and more fish or corals, or more sophisticated equipment. I'm happy with my tanks the way they are, more or less. I maintain them daily and weekly, and enjoy them often.