I've never used an external pump before but the new setup I'm getting is set up to use one. It has a manifold to use 3 reactors or the third as a calcium reactor which I'm not doing. Most likely I will run 3 reactors, one gfo, one carbon, and one bio pellets. I need to know what size pump and some brands preferably something reasonable and not excessively noisy. It will be in a stand in the living room. Any help is appreciated. I have a 6 month old mag 12, a brand new in the box mag 9.5, and a six month old mag 5 if anyone's looking to do some trading for a pump. I believe the pump that was on the setup I'm getting was used with a 1" bulkhead in the sump.