ive got the catalina 500 w titanium. the thing is a beast .
mike
they actually have a 300w model now. But i would do 2. I feel it's good to have a redundancy.
Eheim Jaeger
definately do 2x250w vs 1 400w. it will give you a slight bump in wattage and give you some redundancy
All heaters are garbage, and rely on a cheap thermostat to switch on/off. Get a dedicated controller like a Ranco or at least an aquarium controller, and either use the heater setting as a fail safe or just get a heating tube.