Backyard Aquaponics
A place to discuss aquaponics

Hi all,

Been reading this site intensly for the last 2 weeks. I am a long time aquarium owner and am love the idea of aquaponics. Due to work and other commitments I cannot start work building a system until Jan 08, so I will spend the next couple of months planning and sourcing parts and materials. Help me design a system.

Parameters:
The system needs to be able to support at least 100 fish (silver perch), as I have to buy in lots of 100. I also have silver perch in the farm dam. May need to support more fingerlings as the first batch get eaten.

Needs to be in the medium stocking level range - because it will be at my in-laws farm about 1hr from where I live. In-laws are really keen to do this as well but they have zero experience with keeping fish so low-medium stocking levels will be needed to ensure we get off to a good start.

Space is not really an issue as it is on a 60 acre farm. I have access to both flat and sloped areas with power available. Property faces due east, located in Western Sydney NSW.

Fish tank - I can get poly tanks about 3000L and 5000L for $1000-$1300 locally.

Flood and drain GB's with auto siphon.

I am ok with wood and will probably make the grow beds but any ideas on sizes and materials would be good.

A single pump to support GB's for 100 fish load. What size?

GB media - I can get 10mm gravel locally is that ok (what are people paying for this?), other options.

Plants: pretty much wanting to grow herbs and vegies. Tomatoes’, basil, coriander, margarum, peppers, cucumbers etc.

Idea's on how to manage the cycling of system when 100 silver perch fingerlings arrive. Now I have experience cycling aquariums and the concept should be the same, but I am concerned about 100 fingerlings in a new system. I know in the US a lot of people use fishless cycling with pure amonia, can we get pure amonia in NSW?

Anyone else in Western Sydney ?

Ok let’s see what ideas people can give me, I can then take back to in-laws to discuss locations based on that setup.

Many thanks, I know there are a lot of questions.

Ok Skygazer to stock 100 fish safely, with no experience.... a 3000ltr tank would probably be about right....

That means a minimum of 3000ltrs of growbed capacity.... to provide for a safety buffer you could be prepared to look toward twice that as your system matures and the fish grow out... (i.e to approach the 2:1 ratio)

Pump.... buy the biggest, best one you can afford... must be able to handle solids.... I suggest look at the Ebara pumps that Joel can supply.

Perhaps a second pump, in case of emergency/failure.... possibly some additional air supply...

Growbeds... if you're planning on using gravel... then they have to be capable of supporting the weight of the gravel and water capacity of the growbed.......

Growbed needs to be of non-toxic, non-leachable material......

If you're out Western Sydney way then you probably need to consider water temperature in your system as well....

You can get pretty hot there in summer and downright bloody cold in winter... too cold IMHO for Silver Perch, or at least too cold for any growth.

Unless you are prepared to provide additional heating..... options....

Can you either partially submerge the tank into the ground... or can you house inside a shed..... insulate around the tank to keep temperature down in summer and more particularly up in winter.

Easiest design principle would be to look at growing Silver Perch out from advanced fingerlings to plate size in 6-8 months, then maybe look at trout through winter.

Excellent points there Rupert.

Tanks will have to be outside at this stage but I can definately bury them as much as I can be bothered digging.

Trout in winter will be perfect ! do they have a similar growth rate / bio load as silver perch in an AP environment?

Trout have one of the fastest growth rates and "food conversion" rates of any aquacultural fish

10mm drainage gravel costs me ~$56/metre if that is any help.

Really need 10-12 months to grow out SP fingerlings to 600 grams unless you get them slightly larger and can keep the temp up around 22-25c

SP winter okay, just don't grow...I got mine in nov 06 and by Jun the water temp was too cold for them to eat enough to put on weight

3,000l of GB space will carry 90kg of fish, so if you start eating them at 500-600grams then you won't need to worry about larger GB space

A good size for GBs are 2m * 1m * 300mm or anything resembling that as you have plenty of room

3,000l tank is a nice size also, what you need to take into account if you do auto siphons, that at some time all the GB will be flooded at the same time so 1,200 litres would need to be in reserve either in a sump tank or from your main tank - just some thoughts for you

Skygazer - you have a number of different options. You can go the powerful pump on timer option like Rupert is suggesting, or you could go the smaller (cheaper) continuously running pump (or 2 to provide some redundancy) in sump, autosiphons in beds and venturi siphons in fish tank type design like myself, Michael Ferrini, Les (sort of) and a couple of others are employing. Some people find autosiphons a bit of trouble to get right at the beginning, but IMHO this type of setup is well worth looking at.

Another alternative is to run continuous pump/s straight from fish tank to grow-beds with autosiphons and gravity return straight to fish tank (save you buying 2 tanks.

good thanks


ok thats fine, don't mind if things slow down a bit in winter, or by then I might be able to install a pool solar heater


So based on 2m * 1m * 300mm, I will need 5 to make 3000l of GB spare, is that correct?



This is where I am not entirely clear so bear with me a little. First trying to work out where you got the 1200l from. Is it based on estimated 60% of 3000l GB space is taken by GB media (gravel) leaving 40% water capacity ie 1200l ?

Secondly if I add a sump: I gues it would need to hold at least 1200l, then does that make total water capacity in the system 4200l? or does it come from the fish tank?

If I don't have a sump, I can see the water in the fish tank dropping to 1800l would that be ok? Thinking ahead I don't see how I could ever acheive the 2:1 GB:Fish Tank ratio or does the total water volume in the system not count.

silvers will survive down to 2C, they just won't eat. Trout have more precise water requirements, higher DO, cleaner water etc.

Use one of the farm dams to raise them if this is feasible, grow bed location wise.Silvers will grow out in a farm dam at low stocking densities to a kilo in 12 months. They are one of the few finfish that grow quicker in dams than recirc, (omnivores,greater range of food available.)

You could simply pump from your dam to the growbeds and drain back to the dam. Low maintenace stocking rate in a farm dam is 200 per hectare of water. Buy small fingerlings now, chuck a bale of hay on the edge of the dam water to get the little bugs going for fish food and away you go. They will require very little maintenace and supplemenatary feeding at these stocking levels.

When you want to harvest down the track, simply purge in salt water 5ppt for a few days.

Don't worry about getting gbs up and running right now if you use a dam, nitrate build up will not be an issue at low stocking levels. Even if the dam is a cattle watering dam etc, provided you can reasonably locate gbs, that is how I would be going.
Welcome and most of all enjoy.

Hi Veggieboy,

Yes I wouldl like to use the continously running pump method with autosiphon, I can understand how that works and I think is a good reliable long termsolution with a small amoung of simple maintenance.

How long would it roughly take to autosiphon a 2m * 1m * 300mm bed with gravel?

I'll check out the systems you mentioned. Thanks

Where can I find info on the venturi siphon

Hi twintragics,

Unfortunately the dam is continuously fed by a moutainside stream, and overfows to a major local river so I have to be careful what I stock in it. I don't think the nitrate levels will ever get very high, but I will take a test kit out there in a c ouple of weeks and have a look. It could save a lot of hassle and make a very simple setup.

It wouldn't matter if silvers got in the local river system, but you prolly don't want ur hard earned going over the overflow, so to speak. Continuous fed dam from mountain stream will lead to higher DO and higher potential stocking densities, all good. If you have some way to filter your over flow to prevent fish escapes,perhaps you could put a few bucks there that you would otherwise spend on fishtanks. Could be something as simple as a few pickets and some flywire screen, perhaps.

It sounds like you have a few options and best of all, some space. I am jealous as hell!

The time it would take to drain the grow-bed depends on how big you make your siphon. The inflow into the bed needs to be a reasonable amount less than the outflow of the siphon to ensure that the siphon will break reliably. I only run a 1 bed system at present, but as I add more beds, my flood and drain time will extend because while I will increase the pumping rate overall for the system, I'll not do it proportionate to the addition of beds.

My bed is 500+ litres and to be hones I can't remember the fill/drain times. Would be recorded somewhere on my thread.

The venturi drain as I refer to it, and as used by myself, Les and Michael, consists of a standpipe connected to the fish tank drain, with another pipe around the outside. The outside pipe is longer than the inner one and has crenelations around the bottom. The result is that as water flows into the top of the drain pipe, it is sucked from the bottom of the tank between the inner and outer pipes, before exiting over the top of the inner pipe.

I'll post a link to my thread. I don't update it much these days - but it is kinda long. On the first page though there is a summary I did a while back along with links from that summary to some key pages in the thread. If you look at these you will see some pics and a description of the style of system I have adopted.

HERE is the link skygazer. I am calling the siphon in the fishtank a venturi siphon, but it is not striclty so. Recirc aquaculture people often use venturi siphons, which instead of having the outer pipe - have a hole low on the inner (drain) pipe. As water flows over the top and down the drain pipe, the venturi action causes some water and the poo to be sucked in through the hole. The reason I don't use this method is that if the pump in the sump failed, the tank would drain through gravity to the highest level of the pipe that comes from the drain to the fish tank. Alathough for me this is only about 15 or 20 cm below the standard fish tank level - I would lose this water by overflowing the sump and when the pump came back on (eg after a power outage) there may not be enough water in the system for the bed to fill and the siphon to kick in.