Thanks! My sponges are cleanish. I've rinsed them several times since this rattle started. I'll definitely try shorting the hose, I had not thought of that. I tried the foam under the pump and noticed the hose didnt fit properly any more. Sand doesn't get in my pump either. Do you get sand in your pump chamber area? If you don't, maybe i have too much sand. I definitely have sand in my pump chamber area. I wondered if maybe the black piece that connects to the hose is rattling...the dual part that water flows through into the main part of the tank.
Hello! I don't have another tank to test it on but I did put the pump in the open water outside of thr pump chamber, it was quiet. I'm not opposed to getting new pump but I really think it's touching the glass or chamber wall causing the rattle. Initially I did think it was the pump. I lubricated the metal rod, it didn't work. And with more trouble shooting i realized the pump didn't rattle in open water outside the chamber.