Noisy return pump.

[Dan1789]

I have a Mag 12 I use as my return pump. The impeller broke the other day and I cleaned the pump and replaced it. Now it is very loud and kind of makes a surging sound. It sits on the bottom of my acrylic sump but even when I lift it off the bottom it is still too loud. I also have flex tubing coming off of it. Any ideas on what to do? It's driving my girlfriend crazy.