DIY swirl filter #1

Here’s the tutorial on how to make a swirl filter out of a bucket, some garden hose, 4 zip-ties, a piece of pipe, and some silicone!

This filter was made for the Timber Prototype Tank #1 project.

It was fed intermittently from a reservoir that pooled water that had drained from 4 prototype grow beds, totaling around 110L including grow media . The reservoir was necessary because the output pipe went below the main tank on it’s return journey, and needed extra pressure to start flowing.

Stare carefully at this! It’s better than my written instructions, it doesn’t get much simpler than this! The snails pictured formed a successful colony for months, feeding on grow-bed waste material.

Do It Yourself!

The Hose input bits:

  1. Decide where your water line will be. This is where the top of your stand-pipe will be later on. Recommend leaving at least 1/5  of the bucket above the water line.
  2. Drill or cut a hole in your bucket somewhere above the water-line. This will be where your hose enters the bucket. since it’s above the water line, leaks won’t matter, but still try to make it as neat as possible – it will help it survive someone giving the hose a savage tug by accident.  You’ll want the hole a bit oval shaped if you want the hose  to come in on the same angle as the bucket (pictured).
  3. Decide where you want your hose to sit. Poke your hose through your new hose hole! Stretch it around to the opposite side of the bucket, a few inches below the water line. Don’t go too deep though, stay in the top 1/3 of water depth.
  4. Drill a hole through the bucket on either side of the hose, near the end. Zip-tie it to the bucket, with the ratchety zip-tie bits on the inside. Make sure you get it at the depth you want!
  5. Do the same a few inches back. This second zip-tie sets exactly where the hose is aiming. Try and put this second tie perfectly horizontally across from the first. This will ensure the Swirl motion of the filter isn’t disrupted, and will flow around the bucket happily without hitting the top or bottom.
  6. Throw on a few more zip ties, for strength. Evenly space them along the rest of your hose, snaking it back to the hose hole.
  7. Play your bucket like a drum, to ensure structural integrity. Reggae recommendedTighten all your zip ties for the final time.
  8. Give all zip tie holes a wipe first.  Seal all zip tie holes with silicone, dry for 24 hours. Try to inject silicone through the zip tie holes, from the outside. Give a smear, get into it!
Th swirl filter installed on the Timber Tank #1
The swirl filter installed on the Timber Tank #1

The stand-pipe / drain:

  1. Pick a pipe for your stand pipe. From memory, ours was 20mm. You could go larger than this if you are expecting high in-flow, but the higher flow rate you feed a swirl filter, the less effective it is at collecting small particles. Our inflow was from a 25L jug that was approx 30cm (1′) higher than the swirl filter, connected with garden hose. Intermittent flow.
  2. Drill a hole in your bucket the size of your pipe. The best position is the center of the bucket, but this can make it more difficult to clean out. We offset ours so we could clean it safely without disrupting the stand pipe.
  3. Poke your pipe through the hole until the end is at your water height. Mark a line on the pipe where it meets the bucket, and another mark 5cm (2′) below the bottom of the bucket. Take the pipe out of the bucket, and cut your pipe to length on your second line.
  4. Put your stand-pipe in place with the extra 5cm of pipe sticking out the bottom. Wipe down the pipe and the areas of the bucket around the stand pipe hole so the silicone will adhere. You can also roughen the surface with sandpaper etc, it will help the silicon grip the plastic.
  5. Apply silicone liberally, on both sides of where the standpipe meets the bucket. Leave to dry for 24 hours, (OR read below for addition strength).
  6. (optional) As you can see in the pic above, we added an extra shield around the top of the stand pipe. You could achieve the same effect by cutting some holes in a small plastic bottle, wrapping it in mesh or material, and placing it over your stand pipe.

If you are having trouble plumbing a pipe through your bucket, here’s a trick from a different project that makes the seal stronger and easier to do, plus it costs nothing!:

Cut two short sections of pipe, and split them long-ways so the become a C. Slide that onto your pre-siliconed pipe and bucket meeting point, on both sides of the bucket.
Cut two short sections of pipe, and split them long-ways so they become a “C” shape. Slide that onto your pre-siliconed pipe and bucket meeting point, on both sides of the bucket, wriggle them around a little. Add more silicone on top, and smear it on there! You could add more layers of larger pipe “C”s to strengthen further.

Make a lid:

The lid options are up to you, just make sure there are small air holes, and not much light gets in.

We cut a circular disk of plywood that fit inside the top of the bucket, then added fence palings on top that were 10mm wider than the bucket, so it held itself in place nicely. There are some pics of the lid being cut out @ Timber Tank Prototype #1.


To get the gunk out of the swirl filter, we just started a siphon with an old piece of hose, and ‘vacuumed’ out all the gunk into a bottle. The bottle of gunk was then poured into one of our snail breeding tanks, they love it.

So far this swirl filter has successfully run  for over two years, no problems.

That’s it!

Any questions or comments, let us know. We hope to get some budget for methodically testing many swirl filter designs against each other, some time soon. Fingers crossed.

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