Here it is....... Clean out your waste tank. Pretty obvious eh? Well, It wasn't for me. I didn't really think it made that much of a difference. But, I have been experiencing weak vacuum when I pick up the wand. Suction on the carpet was good, but it sounded like I was sucking shampoo when I lifted the wand after a stroke. I'm sorry to say, it has been 2 years since I gave the tank a good cleaning and the bottom of the tank was free of debris, except on one end there was about four gallons worth of sand and carpet fiber (mostly sand) built up. On the other end the sides of the tank were covered with muck and the baffle holes were literally closed also. So, I found the cause of the vac loss has been discovered and the tank is now back to a respectable state. Considering the cost of a sapphire tank is about 2500.00, you'd think I'd take better care of it.