Backyard Aquaponics
A place to discuss aquaponics

Hi guys and gals!

What a great web site!

I’ve been cruising it for a while now and though about time I spoke up.

I’m a ‘mature age’ (some might disagree!!!) Enviro Sci student at RMIT. I also have quite a few years under my belt with marine aquariums and filtration /system design (have run my own business for many years) and am currently involved in 2 projects: One with Black Bream at the DPI facility in Queenscliff and one at RMIT’s Bundoora campus with marine rotifers).

So combining my studies and my experience, plus my love of gardening, organics, sustainability, etc, aquaponics is a very logical step for me.

Thanks fully I have some space in the back yard and have come up with a smallish system I want to try. I’ll post a plan later, but in short I’m looking at 2x 1000L IBC’s for fish, flowing into about 6x ½ 200L blue drums for grow beds (possibly with some grow towers as well), flowing into 3x ½ 200L blue drums for yabbies and them back to a sump. That’s just the very short and rough version for now, but there are more gadgets and gadgets I’ll try to incorporate as the plan evolves.

Now, I’ve searched the forum high and low, but have not found any definitive answers to a few Q’s:

1. What fish are Victorians (Melbournites) mostly growing? I’d been pretty keen to have 2 species (1 for each IBC) so say maybe Trout and a Perch sp?
2. Where are Melbournites sourcing their 200L blue drums from (I’m in Eltham)?
3. Given Yabbies are fairly opportune feeders, would I be better off having them first in line from the outflow after fish tanks? I’ll be using a bottom siphon to remove as much of the settled fish waste as possible. I guessed this waste would make for a good food source for the yabbies?

That’s the first few Q’s, so I look forward to chatting with you all more and getting this project off the ground!!!

Aaron.

Hi Aaron go to members systems i think its a good start. Blue drums try the local concrete plant.Fish silver perch cod and trout in winter

Welcome to the forum Aaron,

I will leave the 1st two questions as I am a little north of Melbourne

With crustaceans, I am of the opinion that they prefer slow flowing water and as such it would be better to run the yabbie tank(s) in parallel and have a reduced water flow through them.

Most of us use the fish waste as a nutrient for the veggies and thus use the pump to shoot it up to the grow beds. - Simmo is the guru on marron so may be able to provide more useful info on food etc for u

Silver perch seem to be the staple AP fish (apart from tilapia - but they are banned in all states except WA )

FF,

Have been though the systems, but admittedly only focussed on the few that seemed along the lines I want to go.

El,

Thanks for the welcome.

Understand the lower flow rate for the yabbies. As I noted, the system is still mostly in the design process and ‘in my head’! IF… I did have the Yabbies in-line, I’d use a baffle system of some description to lessen the direct flow rate for them anyway.

Regarding pumping the waste “up into the grow beds”, I thought the plants would only uptake dissolved nutrients? Having the yabbies process the larger fish waste first (into smaller particles) would aid in nutrients being made more available for the plants (and bacteria). It might also lessen the risk of fowling?

It seems there’s a lot of a posts where people are having problems with excess nutrient levels. Discarding for younger or inappropriately stocked systems (re: insufficient bacterial colony) that’s just indicative of excess waste products from the fish. Combine that with a few posts were issues of fowling have occurred and it suggests solids are not being efficiently broken down. Just a thought…

The research continues!

Aaron.

Definitely food for thought Aaron

AJ, AP is definatly a works in progress. My dramas were more due to a SHARP downward shift in temp. You get a feel for how much too feed.

Re the solids, they are trapped in the gravel and a slowly mineralized and worked apon my micro flora/fauna, most of us have found a varety of worms that have set up shop of thier own accord. I'd be wary of collecting and removing much solids as i'm fairly sure this is where the majority of P and K come from, esp. since systems that remove solids tend only to be able to grow leafy greens. True that pants are only going to take up water soluble components, but i'm sure there is a variety of complex bio/chemical reactions that happen in the root zone. Also once insolubles are "worked on" i'd be surprised if they don't become soluble. Many compounds are only one reaction away from becoming soluble I think sulpher powder is used in agriculture...........thats not soluble, but makes its way to the plants somehow

Anyway, its all about giving it a go in your own way, so get to it Let us know what you find.

Have fun and welcome.

Aaron - firstly welcome. To answer some of your queries:



Some of us have worms in the gorw-beds. These help to process the solids and left over plant roots etc. Solids don't tend to be a massive issue - depending upon the type of fish you have I guess. All my experience is with perch. The solids tend to be broken up by such things as going through the pump and the flood and drain cycling of the beds. SOlids get trapped in the gravel and are processed by the bacteria and the worms.



The excess nutrient levels have nothering to do with the solids being efficiently broken down. As you are probably aware from your aquarium background - the ammonia produced by the fish (both in poo/wee and through gills) are converted to nitrite by nitrosomonos and the nitrite is converted to nitrate by nitrobacter. The excess nutrient levels you speak of may have been ammonia (meaning nitrosomonos not working efficiently enough), nitrite (nitrobacter not working efficiently enough) or nitrate (not enough plants or right type of plants to remove this from the system). The problems you have read of are normaly the result of either 1. system not cycled properly yet 2. feeding pattern changed to quickly resulting in ammonia and/or nitrite spike 3. lowering of ph resulting in nitrosomonos and/or nitrobacter working less efficiently 4. insufficient planting or not right planting. There is also a possibility that not enough media used to support bacteria collonies - but it is rare to see that one here.

Using yabbies to help break down solids will not solve any of these problems IMHO (not that I think it is not a good part of a system - just not something to solve the described issues). Solids removal can help with some of the issues - but is not recommended by most of us - cause you are basically removing the good stuff - best to just manage it appropriately.

This is a short description - happy to continue the discussion if you have queries on any individual point.

:-)

Too slow

but worth the wait

As another newbie I've got another question.

I have read of extensive debate about f&d (it would seem the majority of the forum) versus continous flowing flood (rare or accidental occurence due to blockages and L. Wilson). Where is this debate? Is it in one spot or spread all over the place?

While many posters seem to favour f&d many of their systems contain nft and floating raft components which I would have thought are related or at least similar in some aspects to CFFlod?

Stuart

Stuart, I think it's spread all over the place. The concern about continuous flow with no f&d is that dry spots may develop in the gravel bed. I ran a small prototype like that for a short time, and it was definitely a problem.

Stuart, there is some discussion here, have a read of it

Thanks for all the replies!

I guess I have to try and stop my thinking from being too aquaculture/aquarium based, where solids removal is one of the pivotal aspects of system design.

Steve,

Work in progress hey! Comparing AP to aquaculture and aquariums, I see AP as more grass roots at this stage. The technology and system design on both AC and Aq is much more complex and advanced than the vast majority of the AP systems I see around. But that’s a good thing, as it means there are large developments just waiting to filter down to AP.

I guess the other issue is the basic idea behind AP is to grow your own food. I’m sure this comes back (for most) to cost, the environment, sustainability, etc…. So unlike AC (which is a commercial venture in most cases) and Aq (which is for display purposes) some of this more advanced technology and methods, is either not necessary, or its cost outweighs the point of getting into AP to start with.

Regarding the solids, I had not considered the micro/macro communities of organisms that would set up home. So it makes sense that a certain amount of solid waste would be beneficial. The issue would still seem to be having the balance between feeding, waste generation, sufficient microbial communities to break it down and sufficient plant numbers to utilise the nutrients.

I can sooooo see a nice uni projects developing here

By the way, what fish are you growing?

VB,

Was not neglecting the nutrients coming from urea. Solids (re: excess food and fish waste) removal is a key aspect of AC and Aq systems as these solids to form part of the source of ammonia, nitrite and nitrate as they break down. Particularly in marine system these solids also form a source of VERY unwanted phosphate. AS noted above I guess I need to sway my thinking slightly.

However, your reasons for nutrient excess are exactly what I’d have expected. Basically the same as in AC/Aq.

My plan for yabbies was not simply to break down solids. I want them as another culture food for us and to simply increase the biodiversity in the system. However, with their addition, I figured there may have been some advantage/disadvantages to placing them in a particular stage of the system. Seems not from what most of you have noted.

Aaron.

Welcome Aaron!



Right on.

AJ, i've got a few jade perch, around 30 odd silver perch, and around 10 - 15 tandanus catfish.

I think sometimes in agriculture (maybe AC too) the more advanced technology is required becasue us humans continually try to isolate system.

I think you'll find that the stocking densities that can be had with AP are very high, as is the plant yield, while the systems themselves are very LOW tech. I guess thats where the definition of AP comes from, the negatives of two systems cancelling out each other.

You're right about coming from an AC or AQ background. It is easier to teach someone with out pre-conceptions. I had that problem when i moved into refrigeration. I would have been better off NOT knowing about pressure/temperature relationships, it just got in the way of what they were trying to teach me

Have fun

Steve