Funny you should ask! I am neurotic about noisy tanks...hehe. I definitely splashed down but, the output is threaded so I put some pvc pieces and elbows to make it quieter. It was weird tho....with 3 elbows on it, the water level was fine, but when I tried something different, with 2 elbow, and a straight piece...the water went too high? Go figure! I have 2 elbow and a straight pieces flowing the water against the glass in the sump and then down...very quiet now! The skimmer itself is very quiet as well.