Why install a bottom drain ?
For 3 years, I didn't have a bottom drain. Leaves and other debris which got by the skimmer would have to be removed with a net, which was a back breaking chore. Black muck (mulm) would accumulate on the bottom of the pond till it was 6" deep. When fish stirred up this muck, Nitrogen bubbles would come to the surface of the pond and lower the dissolved oxygen levels. Now that I have installed 2 bottom drains, the bottom of my pond is completely clean. The drain removes everything except rocks.
Using Gravity !!! When the pump draws water from the settling chamber, gravity will force water from the pond through the pipes and back into the settling chamber. Water always wants to seek its own level.
If your are looking for a low maintenance pond, I would definetly reccommend a bottom drain no matter what size it is.
Flow rate depends on the size of the drain. A minimum flow rate of 1000 gph for a 4" drain. How many and how far apart depends on the shape of your pond bottom. If your pond slopes to one central point you may only need one drain. If you have a completely flat bottom, you may need several, spacing would be dependant on the flow rate.
Yes, you can, but I wouldn't do it. Your pump would get clogged every hour. A settling chamber is much better, because it allows the bigger particles to settle and not clog the pump. It also provides a safe haven for little fish that swim into the bottom drain.
Commercial vendors offer several models of 4" bottom drain that can be purchased from
$89 to $129 dollars. However, you can build your own for less than $15.
