Backyard Aquaponics
A place to discuss aquaponics

Joel, lets swap notes. I have 3 yrs experience (talking full time obsession and about 6 months of entire time with day job) and you 5.

I have used passive return DWC, recirculating gravity return DWC, nft (didn't think this was any good at all really) medium beds continuous flow, etc.

You obviously have flood and drain to the nth degree.

My input of fish food is 6-7.5 gms per sq metre to produce rapid fish and plant growth. This with 1 kg fish. I keep thinking I've read it wrong but industry claim to use between 60 and 100 gms food per sq metre!

I want to get the commercial side of things perfected in order to realise profits for further research and development of Aquaponic and other bio technologies to clean up industry.

Your notes would take me there that much faster. And my notes help you I'm sure as they will be an ongoing expansion with many statistics.

So? How about it!

I'll give you a breakdown of how I want to design specific systems, the ratios, etc, and you can tell me what I'm doing wrong hehe.

This would save me a lot of time and headaches and I in turn can share all of my experiences and learning to save you time and headaches.

With my current knowledge I have chosen to try the following route with my greenhouse system.

1200 litres supporting up to 15 kilos of fish (intended polyculture freshwater crays - Koura (kiwi bloody yabbies!) filter feeders (not many options perch or carp) and whatever I'm allowed that's a freshwater omnivorous fish. I'd like to be able to eat it. This water volume is for humane fish growth but also proven to accelerate growth in many species and much less disease etc, and thermal stability.

I was always going to go vertical as 16 sq metres soon becomes 8 when you add paths, throw in a pond... It was just how.

I will definately be trying 2 metre lengths of 250 mm diameter pipes cut with planters on 3 sides, 1 per 700 x 700 mm 'bay'. An eventual total of 13 (potential 16 if suspended over fish) bays. Each of these stocked with scoria. 1 pipe provides 1.3 sq metres potential foliage cover.

I will start with 1-2 kilos of fish and 2 pipes. Adding more as time progresses.

Pipes will be continuous flow from the top with heavier feeders above. Many potential crops. Aeration via continuous trickle and s bend gravity returned waterfalls. All plumbing underground till it meets system parts.

Anything obviously wrong?

Moved this to a better spot AA..

I work on my fish feed amounts in kg of fish in a system, feeding at around 1-4% of mass of fish per day, so for your 1kg of fish 6 grams isn't very much by that scale. Though personally I feed my fish when they will eat.. I haven't been weighing my feed at all lately, I have so much measuring and weighing that I'll have to do soon when I take carefull notes of the barrel systems production over spring and summer, that I really can't be bothered with my other systems at the moment..

If your greenhouse is only going to have vertical growth, do you know roughly how much volume of medium you are going to end up with? ie, how tall are they going to be so that a ratio of growbed to fish pond can be worked out, I'm a little concerned that you will have fairly low stocking of that water because you might not have enough growbeds... Still all this means is that you won't be able to have as many fish as is possible, this isn't such a bad thing, as you said, you are trying to go for 'humane' stocking of fish... But I'd definately want to know the volume of the medium in the pipes....

Don't really see any major dramas with your plan, I guess it can be a little difficult for me to visualize exactly the system that your planning, but from what I can see, sounds great..

How was your DWC, successful? Have seen some impressive results in the past, but not tried it myself, I'm interested in trying it soon one day, especially as it can be done small and doesn't take up much space.

On measuring food. With one system it was easy. I'd note down the date I bought food, how much there was, and what type. As soon as I ran out I had an accurate but approximate daily intake.

DWC kicks butt for fruiting plants in Aquaponics but is so costly for set-up (lots of big plumbing and fittings).
Recirculation is the key to DWC and goes as follows
1-6 tomatoes. 7 times per hour water turnover and 6 inch waterfall return drop. Count total water in planters not including your fish tank.
6-12. 9-10 times recirculation. 8 inch drop.
12 - 36 tomatoes. 12-15 times recirculation. 12 inch drop.

Water enters planters via 13 mm at top but pushed down via 10 mm reducer to cause circulation in each planter. Water exits opposite side and into gravity return lines (25 mm).

This is at 20 litres per planter. 1 lb fish per planter. Plants were fixed with 6 inch planters filled with hydroton.

Total system bio-specs ratio 1 lb fish, 2 gallons medium, 4 sq ft canopy.

I think one reason I ran successfully in so little medium in several system concepts was the continuous planting schedule providing massive housing in root zones for bacteria. (Ever seen DWC roots?)

This is why I think nft was a bit crap. not enough medium or space for the root zones. I tried mediumless as well - rubbish!

However, mediumless would work for leafy crops like lettuce but then you're stuck with all that solids removal and resultant waste and pollution.

OK, back to greenhouse throw as many questions as you like my way.

Each pipe will hold approximately 80 litres medium.
1 kg fish to cater to each pipe? (half fruiting half leafy crops)
1.3 metres potential canopy per pipe.

The DWC recirculation rates were to ensure enough dissolved oxygen in larger systems as the water had to travel further.

Greenhouse...

What is the sum for working out volume inside a diameter I can't find it....

2 metres x 225 ml diameter. Anyone? Then this times 12. That's my medium volume.

This will be the volume of each pipe. Each pipe will occupy a bay 700mm x 700mm which due to being vertical will provide 1.3 metres potential canopy. I will build up to 12 of these.

So yes, figures I REALLY want to verify - after we have the total medium volume, how much fish would you use?

And do you include canopy in your sums i think with vertical growing it will be different, or is that what you were saying earlier, "might not have enough growbeds".

If I got some bottom feeders I could increase my bacterial populations by adding medium in the water body itself and just drain through it into the pump. But hope I won't need to.

I've yet to choose black or red scoria they affect pH differently I must learn.

It is intended to keep bacterial populations working well with stable temperatures, good pH, optimum DO levels, varied Aquatic species, and varied plant species on a perpetual harvest schedule.

Other space will be for a seat by the fish so I can sit people down and let them 'see' what I say.

Your backyard is an absolute credit to you Joel, it convinced me I was on the right path as soon as I saw it.

My friendly irrigation specialist not only stocks huge pipes but ensures me there is no lead or other nasty contaminant. The likelihood of this stuff degrading internally with a constant flow of cooling water is VERY low.

He's going to do some homework for me. He's a good mate and will tell the truth. His Uncle is a Fish Scientist who just bred eels and he loves this stuff. I'll ask him a million questions about many things (pipes and fittings) before I'm done.

The greenhouse looks great, must update pics, only a frame but such a sexy one!...

ps - I can go up to 400 mm pipe this will add medium rapidly.

volume of a cylinder is 3.412 x radius squared x height.

Hi Aquaddict,
I am really enjoying your posts, but can you please use metric when posting volumes/measurements.... I am old enought to well remember foot and gallons but it is a pain converting them when making notes.

Murray

I'd like to apologise myself, i prefer metric too, but damned refrigeration pipe is still sold and bought and talked about in inches.....................

'volume of a cylinder is 3.412 x radius squared x height.'

sorry monya, but it's 3.142 (pie) x R2x H=V

Thank you for the sum.

I have put the conversion tables on favourites sorry.

It's wierd that metric seems harder when you use imperial for a while. All part of the giant leap backwards.

Is cubic metric or imperial?

So one pipe or tower will hold approx 345 litres or .345 cubic metres medium.

With displacement from planters end caps and not filling right up I'm going to round this to 333.3 litres per pipe.

So 12 will be 4000 litres of medium or 4 cubic metres.

Or did I work that out all wrong?

From where I'm sitting I have more medium than fish required. I was planning 15 kilos of fish in 1200 litres.

This looks like the perfect excuse to have even more fish

I'll start with a percentage and work up toward 12 pipes.

What is your opinion on stocking weight to feed one pipe being continuous flow, 333 litres medium and 1.3 sq metres foliage cover.

I'm thinking approx 2 kilos fish per pipe. This would stock my water at 2 kilos per 100 litres - bit high for my liking. I have the option of reducing pipes or increasing pond size still.

Advice?

aaargh thanks rm and i just did all that math! ROFL

It will be 300 litres medium per pipe.

This seems a huge amount of medium to me I guess it is because I am used to playing with Deep Water Culture. I think narrower pipes than 225 ml however I want to be able to put plants at staggered heights on 3 sides of them so must ensure I can do this.

Does 300 litres of medium sound right for 1.3 sq metres of bed?

High or low?

I did some converting to give metric figures of a ratio used for recirculating DWC Aquaponics. This works really well.

I have been measuring space etc outside. I will make 2 DWC tomato buckets up as well, A climbing tomato will fill space vertically, and I can demonstrate the technique for the forumers. I'm quite sure they'd be easily incorporated in the same space. Of course I'll need all systems go to get some stunner tomatoes.

In metric

1 Kilo Fish, 25 litres medium, .75 cubic metres foliage.

With a pipe having 300 litres medium to 1.3 metres foliage I'm thinking

I guess the roots have to be somewhere if they're not hanging in large volumes of water...

mmmm, I'm getting different answers to you AA, not sure where things are going wrong so I'll lay out my workings here...

3.14 x (rxr) x height

3.14 x (11.25x11.25) x 200 (working in cm for all values)

= 79481 cubic centimeters, or 79L per pipe for 225mm pipe.
79L x 12 = 948L total



3.14 x (rxr) x height

3.14 x (20x20) x 200 (working in cm for all values)

= 251200 cubic centimeters or 251L per pipe
79L x 12 = 3000L total

A very big difference there when you change pipe sizes... So if you were to go for the 225mm pipe, you'll have 948L of medium for 1200L of water, by my ratios you're at less than 1:1 so less than 3kg per 100L of water. 30kg of fish is pushing the very upper limit, 20-25 kg would be reasonably comfortable once your system is well established and running well.. So if as you said you only wanted about 15kg would be pretty good, not too much work in keeping it at those levels.

Thats not too bad for what you were after with only using the narrow pipe.. I haven't ever used canopy in any of my calculations, just volume of growbed medium to fish tank volume, running on the assumtion that you have plants growing in most of the medium at any one time...

I hope my calcs are right, I've only had one coffee this morning, brain hasn't really kicked in properly yet...

thanks aquafan
i am dyslexic!! seriously, am forever swappimg stinking numbers!!!