When new the Ks rattle a bit when starting up as the propeller hops on the shaft. After a few days, the shaft gets slimy and it quiets down. No issues with Ks and Wavemaster. IMO it's a great way to get plenty of random flow for relatively little money and very little power consumption. I love the Wavemaster Pro, the only thing is the case is not waterproof. Either put it somewhere where it can't get wet, or put some plastic around it to keep it dry.