I drive a b-class rv (van) with a macerator and 1 1/2" hose. My black tank value was stuck open. It would close almost the entire way but the red light, signifying it was at least partially open, stayed blinking. I was told by several techs that a small piece of tissue was blocking the value and to keep flushing it out. I tried this for about 4 month using the TST tabs - still stuck open after trying at least 20x. Saw Matt's video and decided to give it a try. Added Liquified into my black tank and waited a week. Went to the dump site today to dump. The black tank value totally closed on the FIRST try. I'm sold on Liquified.