Tank Overflow and Sump Plumbing

Im not sure how to make it as quite as possible, but if you want it as quiet as possible i would recommend a "Herbie" style system, you will need a third hole drilled (or use some pvc and run the return line outside your tank like i did). The "herbie" has a main drain, an emergency overflow drain, and your return.... Using a gate valve/ball valve you slowly close the drain off until the plumbing stops sucking in air and creates a very effective but quiet vortex. Simply google search "herbie overflow" and you can see tons of videos on youtube on how to accomplish this.

-Punk-