DIY Aquaponics: How to Make a Hybrid Swirl DWC Bio Filter

If you are stocking your fish tank to max capacity — or if you simply have insufficient bio-filtration (ie. ‘grow beds’ in aquaponics systems), you may notice the water clouding up and solids accumulating at the bottom of your fish tank. Solid accumulation can cause your pump and pipes to clog and even fish fatalities from all the nitrogen build-up. Plus that fishy pond smell… ain’t nobody got time for that.

aquaponics tilapia fish
Prior to installing this swirl filter, we could barely see all our bright Golden Hawaiian Tilapia anymore! Guess after a few years of NEVER being cleaned out, our shallow rain gutter grow beds quit pulling their weight…


We discovered the BEST solution to this problem, especially if space is limited as the case in our small backyard farm, is a swirl filter that also takes full advantage of the useable grow space. Something I’m calling a “hybrid swirl bio filter” — made using a standard 55 gallon drum and 4 inch net pots. Unlike a regular swirl filter, plants are grown out of the top and the plumbing is external to allow roots to grow down without constantly clogging the return pipe.

Materials you will need to build a Swirl Bio Filter:


how to aquaponics diy filter
Drill 3 holes with a 7/8 forsner bit — one at bottom, middle, & top of the drum and install the 1/2” male/female adapters with o-ring (pictured above right). In the bottom hole, use a 1/2” threaded female connector in place of the female adapter (see why below). Create watertight connections using plumbers tape and sealant.


innovative swirl filter aquaponics
Drill 4 x 3 1/4” holes into the top of the drum with a hole saw. Measure the external standpipe to desired internal water level (an inch or two below bottom of your pots). Wait to fill pots with grow media until you’re done…
diy aquaponics solid removal
Install a hose valve to the bottom threaded female connector for periodic removal of solids.


external swirl filter plumbing
The external return pipe uses two 90 degree elbows and one 45 degree connector (to prevent siphon action). The overflow pipe uses a single elbow to divert water straight over and down if the return pipe gets clogged.
diy aquaponics drilling
Drill a 3/8” hole near the lip of each 4” pot to run the 1/4” micro line thru (plus extra drainage holes if not using net pots made for hydroponics)
aquaponics tubing how to
Use 1/4” microtubing and straight barbed and sprayer connectors to create irrigation lines to each 4” pot. Use two hose valves on either side of all the microtubing outlets to control water pressure.
direct seed aquaponics
NOW add your hydroponic grow media — I think Growstones are the best for look and function. Then simply plant up your favorite heirloom organic seeds! I planted crystal apple cucumber, blondkopfchen (“little blonde girl”) tomato, paradicsom pepper, and sweet mace.

Stay tuned to see how everything grows… The fish pond is already exponentially cleaner. So stoked!

~Happy Farming and Green Living~

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