Thanks for all the responses. This forum rocks! You folks have helped me make up my mind. My plan now is to add an inline heater to the Cascade 1200 I have, get rid of the Magnum Pro HOB, then purchase another cannister and add an inline heater to that. I need to research hose sizes and we'll probably go with the Hydors. Having said all that and knowing this "which cannister filter is best" question has been beat to death all over the web, feel free to post what you would think would be a good matching filter to the Cascade I have. I am not happy with the bypass the Cascade has. I have a 125g tank with a couple of 9-10" Oscars, a foot long bull head cat, a 6-7" Green terror and four other 4-6" cichlids. Maybe a Rena XP4? A friend mentioned the Fluval Fx5 but I've read some disturbing reports on those. Thanks again folks. I've got some serious buying and work to do.