How much do these things cost and where is a good place to buy one? Some people seem to think a 46gal is too small for this type of circulation. I just want some opinions.
Call Preuss Animal House http://www.preusspets.com in Haslett Michigan and talk to Rick Preuss or Steve Oberg. They sell a ton of Tunze and I'll bet Rick can and will beat any price. They don't usually sell mail order, but on Tunze I'm guessing they will, especially if you tell them David sent you.
They may also talk you out of it if it's not the right thing to do. They've talked me out of several purchases, sometimes giving me a better alternative and sometimes just telling me to sit on my hands and do nothing.