In the process of setting up a 125 gallon tank for Red Belly's (about 7-10 2" RBP), and I have a Fluval 404 that I just purchased. I also have a HOT Magnum 250 filter I was given for free. Should I use both of these filters? How are effective are powerheads and should I buy one or two? Also, how effective are the undergravel filter systems ( I have one already), I was thinking to maybe set that up with the Magnum, but I dont know what will work best though. I figure some of you piranha experts have some good experiance in this field. I also purchased an Aqua Mist to produce alittle movement in the tank. Thanks guys.