DIY Pond Filter

DIY Pond Filter

There’s something so relaxing about ponds: listening to the water gently churning and watching fish swim lazily by. That’s why many people choose to have a backyard pond – no matter what the size is. Garden ponds provide a place to grow aquatic plants and raise decorative fish. If not properly cared for, however, they may become overrun with algae and pond scum. Adding a filter to your pond removes algae and other unwanted organic materials, keeping the water clear. While a variety of commercial filters are available, you can make a DIY pond filter at home.

What you’ll need:

  • Filter Container (Suggestion: 30 gallon, plastic food grade drum)
  • 1 – length of 1 1/2 inch PVC pipe
  • 1 – length of 2″ PVC pipe
  • 1 – 1 1/2″ PVC slip T
  • 1 – 1 1/2″ PVC threated T (the threads are on the perpendicular opening)
  • 2 – 1 1/2″ PVC elbows
  • 1 – 1 1/2 inch to 1 1/4 inch threaded nipple reducer (or a threaded hose adapter from the pond shop)
  • 1 – 3″-4″ closet flange (its a toilet part)
  • 4 – 1/4 inch by 1 1/2 inch bolt, nut and washer combinations
  • 1 bottle silicone sealant
  • 1 – 2″ PVC ball valve
  • 1 – 2″ shower drain
  • 1 – 3″-2″ ABS bushing
  • 1 – length of hose (1″ hose)
  • 2 – hose clamps (You’ll only need one but there’s no harm in adding extra, just in case)
  • Filter Media or plastic fencing
  • 1 – length 1/2″ PVC pipe
  • 4 – 1/2″ PVC elbows
  • 1 – 1/2″ PVC cross (the X shaped one) these are for building a stand to hold the egg crate off the bottom of the filter
  • 1 – plastic egg crate style overhead 2×4 light grate (or something similar) you get these in the lighting section of hardware stores.

Let’s get started!

Tip: Clean your barrel so it is safe for fish. Let it soak for a couple of days in clean water.

The Drain

Cut a hole so that your shower drain fits tightly at the bottom of the gallon (the grate part goes on the inside of the barrel). Take each part that needs to go through the barrel and trace them onto the side. Drill some big holes around the opening so you can insert the jigsaw. Then play connect the dots with the holes. Trim the holes bit by bit until they fit perfectly.

This drain must be sealed onto the bucket with the silicone sealant or it will leak. Sealant must be applied along the inside edge. Whenever you seal something like this, make sure to wipe down all the surfaces to be sealed with rubbing . Don’t be stingy with the sealant — you want it to smoosh all over the place.

Next, insert a cut piece of 2″ PVC pipe into the 2″ shower drain. The 2″ ball valve goes onto that cut piece of pipe. It all must be glued together.

Attach it to the barrel.

Pond Return

Cut the hole for the pond return spout the same way the drain one was cut.

While holding the flange in place on the barrel, drill the holes for the 4 bolts. The bolts will make sure that the flange stays pressed against the barrel.

Wipe all the surfaces down with rubbing . Goop on the sealant and smoosh it into place.

Wipe down all the washers that will be on the front of the barrel with rubbing. Goop some sealant into the holes and insert the bolts.

Now insert the bushing.  The bushing allows you to attach a 2″ pipe to the flange. Put sealant on the inner part of the opening of the flange and insert the bushing.

The Inside

Cut one piece of 1 1/2″ PVC pipe the height of the barrel and attach the tee without threading to the bottom. From that tee you will need 2 smaller pieces of 1 1/2″ PVC pipe that will extend to edge of the barrel. When the elbows are attached, angle them to face opposite directions.

So this is how it should look inside the barrel. It goes in the barrel, underneath your egg-crate or soda holder grate. Punch a hole in the grate so that it slides down the pipe.

The tee with threading slips onto the top of the pipe; the hose adapter threads into the tee and is held in place with the clamp. The opening that is facing straight up is left open to allow a bit of air to get into the filter.

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