Backyard Aquaponics
A place to discuss aquaponics

Hello I am new to aquaponics. I want to start off with a low budget, small system that is more a vegetable producer.



I have made a plan -
Fish Tank: 54 Litre rectangular tub
Grow Beds: 2x 54 Litre rectangular tubs
100L Expanded Clay
A small underwater light for attracting bugs to the fishtank
Continuous Flow system, using a 100L/Hr pump, backup battery aerator or pump
3 Tilapia and 2 silver perch

Very simple, and seemingly easy to setup. Kinda based on the barrel system, but using tub's instead. I will document the build with photos.

I have a few questions if any experts could help it would be much appreciated!

1) Should I include a Duckweed tub also, as a buffer to any nitrogen spikes & food source for tilapias

2) Does it matter if the Duckweed tub is above or below the grow beds? I prefer it is below, as the nitrogen should be absorbed by the grow beds in preference to the Duckweed.

3)Can the Duckweed tub be at the same height as the growbeds? Or should I use the Duckweed tub as a sump with a CHIFT PIST type system?

4)Which system type is best suited to this scale of setup? Flood n drain? Ebb n flow? Continuous flow?

5)Could I use 3 grow beds with this system (150L expandable clay)? If I did, does that mean I could have 7 fish in the fish tank or will this be too crowded in a 54L tank?

6) Will the harsh Perth summer kill my fish? like 40 degree C water in the middle of the day..

Any comments would be great - I plan to go out and buy the equipment within the next wk or two, its just starting to heat up in perth and I want my grow media up and ready for summer!

I plan to initialize the system using my mum's goldfish water, maybe a couple of goldfish and some seedlings.

Cheers!
Matt

Apparently the container is food grade plastic (Bunnings fish tray).

With the current arrangement you should be able to run continuous flood but you definitely do not have the sump capacity to support you 100 liter growbeds if you wanna do flood and drain. That duckweed tank should serve as a sump tank if you wanna run flood and drain.

If you want to run flood and drain, I suggest that you use an external loop siphon so that you can adjust the water level in the GB pretty easily. I have these PVC siphons on my system and I only need to swivel them to adjust the water level, no need for different stand pipes.

My opinion is that this fish tank is too small for fishes that could grow like perch or tilapia. Goldfish would be my option instead.

How do you plan to plumb the system?

Actually I realize that 54L is too small (it wont even fill the grow beds).
So Im thinking of using a 100Litre 710 diameter x 450 deep pond instead.

Is 30cm not deep enough for a fish tank? There is a 910x30cm pond available that is 150L - this would allow me to expand the garden bed later possibly.. But only if the fish are OK in 30cm of water.

Oh and I think the loop siphon may be a simple and effective method for this setup, thanks for the suggestion. I think plumbing will be with pvc piping & silicon.

Hey Matt,

I started out with similar kinds of setup, many members do it wont be long til everything u look at will look like a fishtank or a growbed... its crazy...

the main issues with a system that is so small is that you have too many spikes and fluxuations.

Temp will move a lot expecially in spring where we have -1 nights and 22c days the fish wont like this at all...

Also with such small volume of water PH Variances and Ammo and Ite spikes will be on a large scale...

By all means Go with it and experiment my freind but i'd higly suggest looking for something a bit bigger as a FT 500-1000L IBC's are a great starter, you can use all the tubs as Growbeds i had many small tubs as gb when i first started.

Stock Troughs are sometimes cheaply found at clearing auctions and sometimes even new.. i know there are some places with like 300 or 400 l ones.

Or a bathtub as a FT is another great idea. Just need to watch the enamel coating isnt too chipped etc.

Getting more water volume will regulate temps and spikes.

Welcome to the Addiction and happy experimenting.

I agree with muftzmn about just sticking with goldfish at the start....they are pretty hardy... silver perch will stress quickly with temp fluxuations... i cant comment on tilapia as i know nothign about them.

Thanks for the info Jamey - I didnt think of the issues with spikes in temp / PH / ammonia with small amounts of water..

Maybe a 200L plastic drum will work? - are tilapia happy with these kind of drums being upright?
Maybe the drum can be dug into the ground, so that temperature remains stable.. Or I can use a heating element to maintain the temperature - I can design a pretty simple circuit to regulate the power during the night. (or just use a timer lol)

How about something like this?

It will work but I would pump straight into the GB then only the duckweed tank so that the solids will settle in the GB rather than the duckweed tank. Or you can use an SLO in the duckweed tank. With this setup, you must run continuous flood as you don't have a sump to absorb the tidal wave in the fish tank.


This is more of what I have in mind with my future system next year.

The tilapias will be just fine in the 200liter barrel though I think they'd love more room to swim around in. A 30cm constant height tank will be sufficient for tilapias but do plan for a fish tank cover in case of jumpers. Mine do jump around sometimes...

Oooh I forgot to mention that if you plan to have a loop siphon but not use them in their siphonic nature, you must flood the GB at a rate lower than it takes for them to activate. A bigger diameter siphon will definitely do the job. I'd say 25-32mm?

Cheers

Here is a thread that might give some ideas about how you could lay things out, Lots of diagrams to look at.
http://backyardaquaponics.com/forum/viewtopic.php?f=11&t=5311

The 100 lph pump would never manage if you are lifting the water more than a couple cm.
The flow rate they list per hour is at 0 head or lift so you need to look for a pump that will move at least the volume of your fish tank at the height you are expecting the water to lift to.

You can grow a few tilapia in a blue barrel but it is still really small so requires more careful monitoring than your next bigger system (there is always an expansion) a system with closer to 1000 liters of fish tank will give you much better water temp stability.