As the title implies, I went ahead and bought the XP2, so I will be replacing the Emperor 400 on my tank with the XP2. No more stinkin shrimp getting into my filter and causing me 3 hours of headaches. I like the canisters more anyway. At any rate, my girlfriend is inheriting a 29g tank, which is going to need a complete overhaul. I'll be giving her the Emperor 400, hoping that it will be adequate. (it has a LOT of bio media in it... the 2 grey expansion things which are designed for extra carbon are packed with Seachem Matrix) Here's my question: If I took the Emperor 400 off of my tank and let it dry up, will that kill off all of the beneficial bacteria? Its no real big deal if it does, we won't have the 29g tank ready for a few more weeks anyway. Perhaps I'll just stick the matrix in my new XP2 and let it stay alive in there until we're ready to set up her Emperor 400...