Description Concentrated periodical cleaner that removes scale, encrusting and grease deposits from the waste-holding tank and grey water tank. Why choose Thetford Dual Tank Cleaner? Removes scale, encrusting and grease deposits No scrubbing required! Technical parts inside the tanks are cleaned as well Prolongs the lifespan of the tanks Convenient small bottle Product Usage: Use in the waste holding-tank , | 1. Add 200ml to the empty tank | 2. Add 5L of luke warm water | 3. Shake tank vigorously. Use in the grey water tank: |1. Add 600ml to the empty tank via the sink or shower drain. | 2. Add 50L of luke warm water. | 3. Drive with your RV for at least 1h, in order to cover all surfaces of the tank. For both tanks: Empty after at least 16 hours at a designated location.