Hello, I'm new to the hobby. I used to have small 10 and 20 gallon tanks but I've been given a 120 gallon tank. The tank came with 16 large (5-7 inch) Jack Dempseys. It came with two hang on filters and one magnum (the magnum is the only one that i know the name of) canister filter. The magnum was leaking around the lid so I had to disconnect it. They guy that gave me the aquarium said he had another magnum that leaked also. Now the water is starting to smell which I've been told is a carbon issue and the water has a little brown tint to it now. I'm discouraged now on canaster filters but if there is a good one that WILL NOT LEAK then I'd be game. I do not mind mult hang on units if that's the better way to go. Thanks in advance for the help