Ok what would you recomend for a external canister filter for a 120 gal some thing not to expensive?
Fx5's are good, but honestly I would go with the Aquatop500UV. "Koi enterprise" has them for really good price. 525GPH 4 stage filter with UV sterilizers built in. For the price of one FX5 you could get two and have more water circulation in your tank. I use them and my water has never been clearer. His heaters are also amazing. Some of the best products I have ever used.
http://www.monsterfishkeepers.com/forums/forumdisplay.php?341-Koi-Enterprise