Backyard Aquaponics
A place to discuss aquaponics

First of all i'd like to thank everyone here for getting me going on this, and for helping with my little trial set-up

Looks little things are starting to come together,
My mate should be delivering 4 Ibc's this week, I've got a fair bit of blue metal, And i've been doing ALOT of reading.

Heres my plan:....



Obviously theres no pluming in the pic...
the 3 grow beds will all have there own loop syphon and overflow pipe going to the fish tank below them
all fish tanks will have there own overflow pipe to the sump
The pipe coming from the pump will have 6 pipes off it, 1 to each of the GB's and FT's
(its a pretty hard-core pump)

The fish tanks and sump will be covered (top and sides) with that stuff they make cool-rooms out of (the above ground parts anyway)
I won't have any cover over the gb's to start, which is why the sump is the lowest... when it rains it will overflow, not the fish tanks.

This should give me 750lt of GB, 1000lt of sump and 2250lt of FT.
thats 15 30cm fish in each tank right?
45 fish, 22.5kg worth

Next to all this will be 1 or 2 bath-tub worm farms and mabye some duck-weed ponds,
also a normal dirt garden for spuds, onions and garlic.

This system will be over-stocked, it should be able to handle 45 fish, but i'll put in 60+, then throw some of them in my dams once they reach "fishable size"
I think 1-2 tanks will hold silver perch all year, 1-2 will rotate between trout and barra.
I'll start will all silvers for a year or 2

If this idea is stupid please tell me now, cause i'm gunna start cutting things in the next few days
Please let me know your opinions, I can think of 1 other way i could use the 4 IBC's but i think this way makes the most sense.
No dought i've missed something blindingly obvious in the 4 months i've been waiting for the ibc's while thinking about this

Not enough growbeds ,, ratio suggested is 2 ( grow bed ) - 1 ( fish tank) so you are a long way short of enough gravel to hold enough bacteria to process the fish poop.

Yup, twice the growbeds.

Apart from that, its great

Hi Mark

Agree with Chappo and OBO. I'd be configuring it so you had twice as much grow bed as fish tank. Maybe cut two of the IBCs in half so you have 2000 litres of grow beds and use the other two as tank and sump.

Also think about CHIFT PIST i.e. bury the sump and pump from the sump to the fish tank then overflow to the grow beds, syphon the beds back to the sump.

Have a look at the link below of how I did mine if it helps.

Thanks for the quick reply's.,
I was under the impression after months of reading this forum:
the amount of fish you can have is dictated by the volume of GB you have...

fishfodder, you suggest 2000lt of gb,...
which leaves me with 120 30cm fish in 1 ibc!!!!!!
it also leaves me no room for transperation or evaperation, filling those GB's will drain the sump dry

Am i completely wrong to assume 22.5kg per 750lt of GB is the wrong way to work this out?

I second the recommendation to rout the water from the sump tank to the fish tanks and have the fish tanks overflow into the grow beds and the grow beds drain into the sump tank. This will send the solids directly to the grow beds where they can be broken down and it will keep the water in your sump tank much cleaner and let you pump stay cleaner too!!!!!!!

I also agree that you probably want more grow beds. 3 kg (intended grown out size) per 100 liters of grow bed is the recommended stocking density in relation to the filtration. You could have those 3kg of fish in as little as 50 liters of water if it is CHIFT.

Example, if you had 2000 liters worth of grow beds, 1000 liters worth of fish tank and 1000 liters worth of sump tank, you could perhaps manage 60 kg of fish (that is the grown out weight.) However, most of us will tell someone with a new system to start a bit lower on the stocking since a new system needs to stabilize before it can really handle being maxed out. For such a system if you are planning on maxing out the stocking, you should probably have some extra aeration and probably a battery backup since that much fish in so little water won't be able to survive long if the power goes out during hot weather.

If you would rather stick with the 3 fish tanks and only 3 small grow beds, I would still recommend adjusting the heights so that the fish tanks can overflow into the grow beds and the grow beds drain to the sump tank. Just only stock the fish appropriate to the amount of gravel you are flooding and draining. That is if you only have 1000 liters of grow bed, only stock appropriately. If you plan to grow the fish to 500 g then you might get away with 20 fish per fish tank.

So, you guys all seem pretty dead set i've got it wrong.
my questions are...

If i've got 1000lt of sump, and 2000lt of GB, won't the sump run dry..
i've got a pump that I THINK needs to be submerged, and is about 25cm tall

also, i thought having the FT and ST burried was a big(ish) deal.....

On the plus side, having 4 GB's 1 FT and 1 ST is less plumbing then my way
i've never tried it, and by that reckoning i can assume i suck at plumbing

I almost wasn't going to post my plans, just do it.....
seems a good thing i did!!!

Your sump tank does have to be at least slightly larger than the growbed volume (liquid volume, accounting for media) or you will run your pump dry. A little larger and you wouldn't have to top up as often.

You are right that 2000 liters of grow bed and only 1000 liters of sump is going to be cutting it close on sump capacity. Most people figure that it takes 40% of the total volume of a grow bed to to flood it with water. I like to recommend that the sump hold 60% of the total growbed volume in order that you have some depth left over at the end for the pump to operate and perhaps even some space to install an automatic top up float valve below the normal low water mark. So if you are restricted to only these ibc's for your system, perhaps you skip one of the grow beds for now. Perhaps later you will want to add it as a DWC raft planting space above the fish tank or something.

Another thing to keep in mind before you start the plumbing, the size of the pipe for the gravity feed SLO (solids lifting overflow) out of the fish tank needs to be a fair bit larger than the size of the plumbing from the pump up to the fish tank. Water under pressure from the pump will move a lot faster than water going out under gravity feed. This has been a stumbling point for many people who sized their gravity feed plumbing from the fish tank to the grow beds too small.

Mark, agree with everything that TCLynx has written, I would calculate it as follows:

40% of 2000 litres is 800 litres so a 1000 litre IBC should be big enough as a sump as long as it is kept topped up (depending on your pumps requirements). An option would be to cut the IBC halves back a bit and make them say 400 litres each to give yourself some more water to play with.

1600 litres of grow bed at 3 kg of fish per 100 litres is 48 Kg, lets say 100 fish at 500grams. Of course not all the fish are going to be maximum size at once so numbers could potentially be higher.

I was originally going to do the above, cut IBCs in half and prop them up on bessa blocks, using the cages with plank underneath as supports.

Sorry just read this again. No need to bury the FT, just the sump. Fish tank should be higher than the grow beds to allow for the CHIFT part of the system to work.

so this then is the plan:



I'll just have to not use one to the GB's, or cut them all abit smaller...

I've got 1 of those 200lt blue barrels sitting around un-cut
but attaching that to the sump effectively will be a bit hard won't it?

I thought it was great to bury the FT and ST to insulate.. stabalise temp?
If its not a big thing i'll still need to cover the sides of the FT to minimise algae won't I?

( there is ment to be loop syphons and overflows on the 2 back tanks, i just got sick of making little virtual pipes )

Use 2 IBC's for a sump you would have a bigger thermal mass ,less top ups and the pump wont run dry very often

Everyone always gets so damn hung up on growbed to fish tank ratio...... The system would work fine, you do not have to have a 1:1 or 1:2 ratio or any other magical number.. You can have more grow beds and you'll have a more productive system, but the system will work fine on those ratios, though I would probably put in a few less fish especially to begin with..

My oldest system runs a fish tank that's over 4000 litres, and a growbed that's probably only about 2-300 litres...

Agreed EB, I think our suggestions are geared toward optimal output with the largest amount of grow bed space and maximum SAFE fish output using the available materials.