Tommy drain/bottom drains come in 4 different sizes (outlet size); 1.5 inch (40 mm), 2 inch (50 mm), 3 inch (83 mm) and 4 inch (110 mm).
When this type of Bottom Tommy Drain is used in conjunction with our rigid pond liners and fitted to the bottom of the pond liner the smooth surfaces on the inside of our liner makes it very easy to keep the pond water clear of particles. A must for gravity fed systems. Ideally suited for draining heaver particles to waste or filter system. We recommended using silicone sealant to make a water tight connection between tank and fitting.