yeah got my answer! I should have known the people on a monster fish site would go big! Fx5 it is. Next question, i want to set it up on the smaller tank so i can move it pre conditioned onto the new tank. the smaller tank being a 47G. my guess is there will be heaps of water movement, is there a way you can slow it down without burning the motor out? or should i just move the filter i already have on the 47 to the new tank and forget about tying to get the fx5 cycled? Now back to saving cash. pain.