I may have gotten a defective one but it kept spurting black water out. I put it together properly (not rocket science), put in clean water and ran it s instructed before putting it in my mouth. As I was about to turn off the test drive and use it , it squirted out black water! It kept doing that every few seconds throughout the cycle. I tried to run water through it a few times but nothing worked. Update - after reading many reviews I think the unit was filled with MOLD! I cannot believe they sold me a unit like this. It obviously was not new. Disgusting and dangerous