Description OLPRO Bottom and Top is a toilet rinse additive that can be used for both top tanks and bowls. It leaves the system clean, free of bacterial and smelling fresh. Formaldehyde free, will not damage the toilet and environmentally friendly. . Directions: Bottom/ Waste tank- Add 50ml of OLPRO Bottom and Top to every 20 Litres of water. Bowl Rinse-Add 50ml of OLPRO Bottom and Top to every 20 Litres of water, then add another 4 Litres of water.     Videos