Betta Tank Outlet

Simple conversion kit to make water changes in small fish tanks painless.
Just drill a 20mm hole in your acrylic tank with the bottom of the hole 3mm below your desired water level.
Slip one of the big washers over the outlet, apply silicone and insert the outlet through the tank from the inside.
Apply silicone to the outside of the hole and slip on the second washer to seal.
The big L pipe is an optional downspout.
There are gratings near the bottom of the tube to prevent escapes.