Here's a pic of a good way to introduce your water into your sump. Make the vent pipe as tall as possible so that no splashing makes it out the top. You can even add a sponge muffler to the top of the vent pipe to silence it even more. The pipe that goes down into the water should be go down as far as possible, within an inch or so of the aquarium bottom, this will make for less micro bubbles.
