Chris,

Do you have a fine oolithic sand bed? The Mag 12 dual/oveflow is going to stir the heck out of your sand bed in a 58. A mag 950(on a restricted ball valve) kick the heck out of my 72 bowfront.

If you're ordering from Lifereef. Specify to make your overflow a slimline model, and make the syphon(front box) to be black or blue.

I have the slimline model, and it take up less room then the full version.