Backyard Aquaponics
A place to discuss aquaponics

yea - will munch it up some and strain it off. The plants will love me long time i hope

Sorry for my delay getting back (had my life to attend to)

Ok, so - my comments in relation to swirl filters and RFF's is all about their ability to remove solids/waste and their place in our backyard AP systems.

Let me explain..

As some members have pointed out in a way, there are solids and there are water born particles and even finer down to stuff we can not see by the naked eye. I class all these things as solids, as we should. A solids settlement filter aka the swirl or radial flow filters are a 'heavy' solids filters and only remove the large waste. Anyone with a finer filter/clarifier after a RFF will know what I mean. These filters are just a basic, basic settlement chamber.

In our systems we provide a protein (food) which provides a nitrogen component and soluble waste (faeces). Ammonia is expressed through solids and across the gills and its the mineralisation and nitrification processes that complete the break down and supply of waste to usable nutrient.

The solids that a swirl or RFF remove, basically resembles a very fine sand. Its just the large stuff. So to say that by adding one of these filters to a standard AP system you can increase your fish or feed load is pure bunkum (hoope I speelt dat rite PJ). The water born particles, gill expressed ammonia and micro particles that still remain in the water column is still quite large and still requires further bio-filtration... whether it be a form of bio digester, MBB or GB's. Removing large waste is improving your filtration but its not the golden pass to stock another x amount of fish... and this is what Im worried about.. Sending wrong messages.

Im happy to be called wrong and I have nothing to prove. Im just adding a different view to what some may take for granted.

I have a finer filter after my RFF and I can tell you now that it collects a hell of a lot more junk than the RFF itself. And that junk is a brown, thick colouration in the water. A solids settlement filter will not remove that type of waste.

On a final (rant) note... Im not against solids removal. Never said I was. My only point was that I am a little sceptical of such filters in a backyard situation before media beds purely for the reason of solids removal.

Make sense

Cheers Charlie - makes great sense

What filter do you have after the RFF or swirl?

Thanks Eric, glad someone made sense of that mumbo jumbo ha ha

The RFF I have built is specifically for the fine tuning the water entering the DWC as we only want nutrient rich water surrounding the root systems. In the second stage or 'clarifier' I chose to use filter brushes in the bottom half of the barrel and then a fine shade cloth in the top half. Im finding that I have to clean it every 2 weeks so far but I think trout season will change that lol

This weekend Im going to set up a large dump valve in the bottom of each barrel so I can crank a tap open and drain each very fast, then I can hose through the waste. Just to make it a bit faster process.

nice work

Your spelling may have improved but your logic hasn't, Charlie. You can argue over the degree of the benefit provided by any of the discussed filter types but the fact remains that if you remove a portion of the fish waste from the system - and the lumpy bits are the easiest and obvious component to target - then there will be LESS waste, therefore less ammonia > nitrites > nitrates in the system, overall. This translates to an increased capacity to carry fish, assuming other factors such as aeration are taken into account. Depending on the efficiency of the filter this increase may not be very much, but it is still an increase.

One could similarly achieve an increase in fish carrying capacity by regular dragging or vacuuming of the FT floor to remove solids. It may be difficult to quantify the increase that removing fish solids offers, but it is real.

Is my reply to you PJ. If your happy that your RFF is allowing you to stock more, feed more.. then be my guest.

What would an illogical, crazy man like myself know...?

1/ You don't have to calculate the number/size of your growbeds for your fish load.

http://www.aquaponic.com.au/Media%20bed ... design.pdf pg 9



2/You don't have to clean your growbeds out down the track.
People seem to think that worms in your system will keep them clean,
but worm castings do not dissolve and will clog the system causing anerobic digestion
that cause toxins to develop and ph to rise.

http://www.aquaponic.com.au/Media%20bed ... design.pdf pg 7

http://www.aquaponic.com.au/Solids%20filtration.pdf pg 2

3/ A growbed full of fish waste will require oxygen for mineralisation hence decreasing the
oxygen for fish.

http://www.aquaponic.com.au/Solids%20filtration.pdf pg 8


4/ you can keep more fish.


All these points came from Dr Wilson Leonard papers/fact sheets

http://www.aquaponic.com.au/fact%20sheets.htm

(just click on the fact sheets you want to learn about)

Very worthwhile reading if you want to know about aquaponics.

Dr Leonard did his PhD on aquaponics and knows more than most about this topic

and in his system he separates the soilds and mineralises away from the AP system.


http://www.aquaponic.com.au/Media%20bed ... design.pdf pg 9


cheers Lou

Seriously Lou? Dr Leonards work has been primarily UVI, NFT etc

Joels personal media bed aquaponics system has never been cleaned out in 7-8 years. It doesnt have a RFF or swirl filter attached.... maybe the bloke who is father and founder of backyard aquaponic media systems has missed something? lol

Dr Leonard doesnt have a 8 year old media bed aquaponic system.... actually, has he ever had a media bed system?

I have a question

Where do the worm castings go?

Trout, I'm no expert but I have asked this question before. Apparently the castings are very good for the plants so some of the castings are taken up by the plants while the rest of the castings are processed by bacteria.

Someone referred to the grand canyon when explaining it to me but of course the grand canyon has had plenty of time for the bacteria to do their job.

I'm not sure how fast all the organic matter is broken down but perhaps if stocking fish appropriately it should work out... I'm no expert though and perhaps someone else can explain it better.

Mineralisation.

Also I was just thinking that worms require energy to wriggle around and grow so they are turning some of the fish effluent into movement and growth and then creating castings so that would mean that the net solid material in the grow bed will be less than if there were no worms.

Does mineralization mean that the bacteria have turned all the organic matter/castings/effluent into inorganic substances?

What are the inorganic substances that one would be left with at the end of this process?

And that's the sludge left in the grow beds....