Our Bottom Drains

 These drains have a 10 3/4" diameter and a height of 7 1/2". The four stainless steel legs can be used to set the desired gap from 3/8" up to 1 1/4", as well as level the drain to make up for any inconsistencies in the bottom of the pond.
The aerated drain has enough mass ( 9 lbs ) for it to stay submerged even with 50 LPM of air going through the low head diffuser. No need for extra ballast like is required with other retro-fit bottom drains.
The air supply pipe is 3/4" male NPT pipe thread, and stays very close to the top of the drain to make sure nothing gets trapped on the pipe inside the drain.
The non-aerated drain has a domed lid to keep waste from settling on top of the drain, and the edges of the lid have been rounded over for fish safety.
The pipe connection is customizable from 2" up to 4" so it can work with any desired flow rate.