Backyard Aquaponics
A place to discuss aquaponics

Hi Gang,

Further to my 'not yet true aquaponics' Yabby System I want to tackle an integrated fish system using a 1000L IBC like on this YouTube video.

What I wanted to do was run by plans by everyone here first just to make sure I'm on track AND to get some ideas from y'all.

OK, so I'll use a 1000L IBC.

Based on a rough plan area of say 100x100cm, once cut down the TF volume should be about 500L and the GB volume about 250L. I might incorporate some NFT channels into it as well but have not yet thought about lengths. At a guess say maybe 4-8 meters of.

I was going to use and auto siphon on the GB itself for simplicity sake, but I like the extra project fun involved in staying with the YouTube design and having a high mount surge tank (which will have the auto-siphon).

Now to my Q's:

1 - Flood volume... With a GB capacity (when empty) of 250L, once filled with media (either scoria or expanded clay) will a 100L surge be enough to wet to an adequate depth? Could it be too much and maybe 50-75L is better? I guess this is question about rough displacement of say scoria or expanded clay balls. Q3 also relates this volume to flood timing.

2 - Fish type and capacity... With the FT total capacity at 500L, less the surge volume (say 50-100L) the FT volume is more likely to max out at say 400L. Now I know stocking capacities and all that are very relative, but my question is what fish would you recommend and approximately how many (assuming I start at fingerling and want them to grow into the system with number starting to reduce as harvesting starts? I’ve seen a range of ratios touted, but I know it will depend on species, size, GB and planning capacity, temps, etc, etc. I’m more after some experienced gut feelings on this one. I was thinking if I went SPs (due to it being summer) I’d be lucky to get away with 20-30?

3 - Pump... I'm thinking something that will provide approx 1500lph. That's about 25lpm which will fill the 75L surge in 3 minutes or 100L in 4 minutes. So a flood every 3-4 minutes. This time may increase some if I ‘T’ off from of the flow to act as aeration and/or to the NFT channels. What are your thoughts on the pump capacity? Should I go smaller and reduce flooding cycle? If so what time frame should I be aiming for?

So over to you guys... thought?

Cheers,
Aaron

Hi Aaron im not far from you and still a novice as in design phase but have seen a few farms in my time.
I would use Murray cod as they are more tolerant of high density. So given you have to have a low density sytem MC can happily exist extensively (low density) at 9kg/500L.
I checked out your refernce to youtube and listened to some other listed, there is an aquaponics song try
http://au.youtube.com/watch?v=bmy5mFfR0 ... ure=relate

Hope to catch up some time.

I'm sourcing 5 of these tanks for my main system I like them because they are cheap and easy to work with. One of the downsides of these tanks is the algae growth, but I'm going to combat that by using silver perch (as they feed on the stuff)

without taking out the middle section like I assume the guy in the vid did, I had 300L Gb and 700l ft max capacity numbers.
I will also be linking min 3 of these type setups.
(its all theory ATM, So I'll leave any further comments until I have had a look at the tanks)

cheers

Easy way to use IBC's.

Make sure the pump provides the flow you want at the stated head height.

If you have a 250 l grow bed, a 100 l surge tank would probably due to flood it but it probably isn't necessary and there are probably better uses for the extra tank, like more grow bed.

Remember, you are talking about a fish tank of 500 l, 250 l of grow bed is not much to support that size fish tank. When people talk about the 2:1 Ratio, it is Grow bed:Fish Tank so twice as much grow bed as fish tank is the 2:1 ratio for high stocking rates. Of course if you have twice as much grow bed as fish tank you will need some way to buffer water fluctuations in the fish tank.

You should only stock 3 kg of fish (planed grown size) per each 100 l of grow bed. If you want to stock more fish but don't want to put in more flood and drain gravel filled grow bed, you will need some sort of additional solids and bio-filtration.

If you want to add NFT channels, you should use water that has been filtered through the grow beds to feed them or feed them from some other solids and bio filtration as the solids tend to catch in plant roots in a NFT channel and cause anaerobic spots and root rot as well as clogging things up.

Hope to hear how your plans go. We like pictures too.

Just to follow up this thread, here is my design 300L Gb and 750L FT

Looks good. Woods not treated with anything.

That's permapine for sure. If you are worried it may leach you should at least paint it with something to seal it. I don't think that the small amount of condensation that may gather on that timber is ever going to drip enough nasties into the water but i could be wrong and thats why i would paint it just to be on the safe side.

siphonphobia's design is much better than the one in the original youtube video in my opinion

1) (despite being treated pine with copper-crome-arsenic in it .. ) the wood support stop the growbed from sagging in the middle ( like one of mine has ) . the one in the video used onle the 2 existing cross bars from the top of the IBC to support the growbed - as I did initially and it WILL sag down a good few cms

my advice to both of you would be - wrap those plastic skins with something to hide them from the sun - black builders plastic / wood decking , even paint . If theyre in the sun too long they'll degrade

and AaronJ - siphonphobia's way of doing it without cutting out the middle section makes for more water volume / more growbed volume for the same footprint
(means more fishies ! )

2) no header tank on top to sit in the sun and collect algae , which will cause pH swings ..

I certainly wasn't diss'n the design, i love it. It takes up very little space and if you have a forklift handy you can always move it around. True though IBCs are not uv stable and do become brittle. I have used them in there cage for my rainwater tanks and just cable tied dark polycarb to them, it protects them from uv and makes them look much sexier IMHO not that i have a thing for pallet tanks or forklifts for that matter.

I have one question.. How do you get to the fish?

oops !

thats where rotating the top half 90 degrees comes in handy - leaves a 30cm wide gap to get access to the fish ....

lol I'm new to the whole fish thing... I just assumed the gap (100mm high by 300mm wide) would be enough

also i didn't realise the IBC's are not UV stable bugger

and the logs are also a worry I have the receipt around here somewhere hopefully they are not permapine ( as I've now read about the dangers)

rofl

don't sweat the small stuff....UV break down on the IBC will take over a year.....and the pine treatment ( permapine ) may take a while too leach.......by that time you probably have expanded the system...and sel a vei...or how ever the frogs spell it

I know someone with a pallet tank over 15 years old left in the sun... not broken but i wouldn't kick it. UV breakdown is affected by other factors like temp and i agree with the last post i wouldn't stress about it at this stage. Get some fish in there and when the fish are ready get hold of an engine crane to lift the top off.