I have the animal style and will never go back, silent, moves a ton of water and I had one get blocked by a piece of nori and it never missed a beat. The one suggestion I would say is for the two drains, use gate values on each. I have my overflow plumbed to exit above the surface of the water in my fuge so it it overflows it makes noise. otherwise the only noise i get is my fish breaking the surface for food.