Comments on: The Queenslander – an Aquaponics System that Really Works

By: gary

gary — Sun, 28 Mar 2010 05:33:02 +0000

John……low dissolved oxygen levels is the single biggest cause of fish deaths in such systems…..but it’s not the only issue.

Other potential problems include clogging of bio-filters (grow beds) and impairment of nitrification. Suspended solids may also function as a refuge for pathogens while they look for a live host – your fish.

Fish gills can be damaged by solids while breathing and solids will, over time, build up in pipework and fittings and limit water flow.

I regard supplementary aeration as being cheap insurance against low dissolved oxygen problems……so I run air pumps in all of my systems.

By: John

John — Sun, 28 Mar 2010 01:22:11 +0000

Thanks again Gary for a very clear and helpful reply.
Apologies, my first post was premature – I found your other pages, with their detailed reasoning later.
I know little about aquaponics and have just started researching it.
Just wondering, if one of the biggest problems caused by retained solids, is deoxygenation, wouldn’t fishpond aeration (with an air pump, for instance) solve that ?
I mean, if you are concentrating on the fish culture, isn’t artificial aeration necessary anyway. ?
(all commercial fish farms seem to have it)
I read about your Queenslander system, but I don’t recall reading about whether you have an air pump, with it.

By: gary

gary — Sat, 27 Mar 2010 20:26:44 +0000

John......you can build an aquaponics system which does what you describe. The secret to operating such a system is to keep it very lightly stocked. That way, the worms (and the beneficial bacteria) can keep things in balance. My concern around solids has less to do with the plants and more to do with the fish. (See 7 Good Reasons to Remove Solids) By the way, solids removal doesn't have to be too onerous. You can catch the sedimentary solids with an orphan sock or a piece of filter foam at the point that the water enters the grow bed. If you keep the system lightly stocked and ensure that you have plenty of aeration, a little system like the one you've described will provide you with clean fresh vegetables.....and (eventually) a fish dinner or two. The key to successful aquaponics is regular water testing and being prepared to act when something is heading in the wrong direction. The Queenslander design concept is for the serious micro-farmer and will provide for much greater productivity (and safer operation) than a conventional flood and drain aquaponics system.

By: John

John — Sat, 27 Mar 2010 07:40:23 +0000

Thanks for sharing your experience.
I want to build a small flood and drain backyard system.
I was really hoping that I could just pump the solid waste onto the top of the plant gravel. I thought it would be a great food for the plants, if it is processed by compost worms. Just wondering if it (solids) is really that bad, for the plants ?

By: gary

gary — Sun, 10 Jan 2010 11:27:16 +0000

Erich…..it would be a crowded little system if you jammed all of those components into it.

For such a small system, I’d propose something like a couple of gold fish (which are pretty resilient) and some hardy indoor plants that don’t require a lot of light. Treat the system as you would a regular aquarium.

For simplicity’s sake, I’d skip the flood and drain and just run it on continuous flow. Let me know if you require more details.

By: Erich

Erich — Fri, 08 Jan 2010 06:29:49 +0000

I have a 10 gallon fish tank with a 5 gallon grow bed. For such a small system, do I still need a sediment tank w/ clarifier, bio filter and sump tank? What will happen if I continue to flood and drain four times a day without these components?

By: gary

gary — Tue, 13 Oct 2009 07:54:59 +0000

Steve........you'll find the diagram here.

By: steve

steve — Tue, 13 Oct 2009 07:31:24 +0000

looks good, look forward to a diagram