bottom drain

If you want to maximize the performance and minimize the maintenance of your pond you absolutely need to install a bottom drain. It is not a matter of opinion, they are a fundamental must have - anyone who tells you other wise is either uninformed or lacks objectivity

The term "bottom drain" is really a misnomer. They should be more aptly referred to as a "bottom filter feed or supply." While a pump in the pond is aesthetically unattractive and can't remove large debris, a 4 inch bottom drain can take large leaves, as it continually vacuums your pond. Those time consuming and expensive pond drain and cleans are no longer required

Remember, you pond is essentially a cage. You wouldn't let feces break down naturally in a rabbit or budgie cage so why is it any different in a fish pond? It isn't, you need to keep your pond's bottom clean of both excrement and other organic buildup to keep water clear and fish healthy in the long run

Bottom drains are not difficult to install, and because of the design, a fear of leaking is unwarranted. A flange clamps the liner down to the drain, the liner acting as a gasket. One of our clients didn't use any glue [not recommended] and the drain still did not leak! Many clients have conveyed regret for not installing a drain, and new clients are amazed at the amount of debris that collects in their vortex
  • bottom-drain-concrete.jpg
    This drain was put into a concrete pond
  • bottom-drain-flexhose.jpg
    A nice smooth shell really helps to channel debris to the drain
  • installed-bottom-drain.jpg
    Geo underlayment should be cut out around the drain before you put in the liner
  • pond-with-bottom-drain.jpg
    This goldfish pond features 2 concrete shelves for plants

installation of a bottom drain

As for the actually 1-2-3 of getting the drain installed, it's straight forward for even the average "Do It Yourselfer"

A hole to house the drain is dug in the deepest section of the pond. The ponds bottom should be bowled to this location with a decent slope - this causes debris to move towards the drain via gravity. A trench is also dug which leads to the settlement tank - this houses the flex hose or pipe which leads to your vortex

The liner is installed as normal - but cut out a hole of the geosynthetic around the drain. It is very important to make sure you have enough liner around all the sides of your pond before you cut the drain in. An "X" cut is made over the sump of the drain. Reach in to make sure both the liner and sump are both clean and dry with a rag. Place some glue on the sump lip, then press the liner down and flatten it out, smoothing out any wrinkles

Put the flange down into place and proceed to screw it in to the sump. This is your seal so take your time and get it right. Trim the liner inside the sump and then add another bead of glue. The liner actually acts as a rubber gasket

Your drain is now installed - enjoy the reduced maintenance, better aesthetics and best of all, superior water quality

  • The drain should be at the lowest point of your pond
  • After the liner is installed, cut the liner and glue it to the drain
  • The flange is screwed right down to the drain body


Tips on bottom drain installation

  • Place a mark on the inside of the drain before you install it. This will help greatly in finding the first screw hole which you can't see with the liner glued down on the drain. This tip is illustrated in the video below [some drain designs don't require this technique]

  • When you fill up your pond for the first time, it is possible that the bottom drain line will be "air locked". As a result of this, very little water will enter the vortex. To rectify this problem, close your gate valve to isolate the vortex. Completely pump or drain out the vortex. Open the gate valve. Water, accompanied by air, will rush in. This may need to be repeated a few times until you don't see any air/water mixture coming in

  • Always install the dome after the pond is filled with a couple of feet of water. If you install it before filling, air will be trapped under the dome. With some water in the pond, the dome can be turned upside down under water to remove the air before being installed. Alternatively, you can drill a tiny hole at the top of the dome so air can escape

  • Never glue the dome on the stem. Although unlikely, you may have to clear a clog one day and this might require removal of the dome

Bottom Drain Install & Pond Plumbing