The SCWD wavemakers are nifty little tools for creating a pulsing water flow in your aquarium without adding any additional electicity using equipment. They are also notorious for clogging and simply stop creating waves. Calcium deposits and other debris builds up in the device and cause it to lose it’s wave making capabilities. To fix this, you can soak the instrument in vinegar or run warm water through it to break up the blockage. If the blockage persists, you might have to replace the device.