Chris's Aquaponics

Mini Swirl Filter Experiment. May 2011
This is my experimental mini swirl filter, aerator and input flow regulator.

The idea is, fish tank water enters through the base of the unit and is directed in a swirl via some elbow fittings. Through centrifugal force, solids are thrown to the sides of the unit and gravity will cause them to fall to the bottom of the tank.

There are 2 stand pipes, also connected via tank fittings through the base of the unit. These stand pipes are tall enough to inhibit solid waste at the bottom of the filter from exiting via this route. 

The first stand pipe returns the cleaner, aerated water back to the fish tank and determines the maximum head of water.

3 connections: -
1 = Fish Tank Input
The second stand pipe is 50mm lower than the stand pipe that returns water to the fish tank. The 50mm difference is a constant. So the flow out of the second stand pipe should be constant as there will always be a 50mm head of water (obviously within reason) above it. This will supply the grow beds.

The reduced amount of fish poo and the regulated flow to the grow bed should help to eliminate fluctuations in the water supplied by the pump. The pump is totally unregulated and subject to changes in flow due to electricity supply (up and down like a brides knickers if you live in Taiwan), debris floating around in the system, fish poo build up, temperature, etc... 

2 = Fish Tank Return
If you can reduce solids and regulate the input flow to the grow bed, you have a better chance of keeping your auto syphons, ‘cycling’,  because you’ve eliminated two of the major varying factors, ‘input flow’ and Poo build up. This will also improve water quality and oxygen within the system.

So, isolating solids, adding air and regulating the input flow to the grow bed. I reckon that adds up to a win, win, win situation…

Tank connectors
Sorry about the poor quality photo’s. I only have my mobile phone camera as I accidently left my camera in the UK on my last visit.

This was my office waste paper basket until very recently. I will eventually buy something more appropriate if successful.

3 = Regulated and cleaned output to Grow Bed
Left hand stand pipe is the fish tank return. The middle is the input from the fish tank pump and creates the Swirl. The right hand pipe (50mm lower than the left hand pipe) is the cleaner and regulated supply for the grow bed.

Grow beds. Filter mounted on the far side of the photo.

If this proves successful, I will fit quick release connectors for purposes of disconnection and cleaning.

This is an experiment and just cable tied to the stand at this stage.

It appears to work! The Swirl is a little ‘pedestrian’ but, it‘s collecting crap at the bottom of the filter (mostly tiny bits of Hydroton). I have no fish yet as my system is undergoing its, ‘fishless cycling process’. First impressions are, it’s doing exactly what it says on the side of the bin, collecting waste! Lol. Also, my Bell Syphon hasn’t failed since fitting this device, but with the increased flow through my grow beds (see later), it was performing much better anyway. I guess it’s a little early to judge the regulator part of my new filter.  Watch this space…

Interconnections between the 2 grow beds. I used to have 3 smaller grow beds and 3 bell syphons but replaced them with 2 larger grow beds and 1 bell syphon (roughly the same amount of grow bed). I found that having just one syphon allowed me to have an increased flow rate for the same cycle time. The same bell syphon design is definitely more reliable at a higher flow rate.

Syphon return pipe.

Bell Syphon.

Interconnection gravel guards.

Hurry up and Cycle so I can start to grow stuff!


Debris collected after just 24 hours with no fish! Syphon still running without incident.


My filter continues to collect crap! Yey


Any updates since May? How did the fish do?