ibc system

[micksnowdog]

ok the more i read the more lost i get lol.
anyhow i scored 4 ibc's for $60ea
i dont want to set up a sump system i just want direct return from the beds using a loop syphon system.
i want 1 bc for murray cod, i was thinking 40 and one for silver perch, 40 again.
i was going to cut the other 2 ibc's into 350mm grow beds, so i will have 4, so 4 square metres and filled to 300mm would be 1.2cubic mt of media.
i want to join the tank ibc's so i only have to run one pump, so pump out of one, return into the other and flow through both.

so i have not chosen the media for my system, i have a big pump capable of 7000lt per hr i think it said, so raising the water say 1.5mt should hopefully pump out 3000lt per hr.

what media? how many fish for 1.2cubic metres of filtration?
will my system work? do i really need the testing kits?

all advice and ideas much appreciated as i am building it all today and tomorrow.

[bigdaddy]

Hi Mick,

So you will have about 2000 litres of fish tank and 1200 litres of grow beds right?

Good start,should really be an absolute minimum of 1 part fish tank to 1 part grow bed, then build it up to 1 fish tank to 2 grow beds.You could just cut the other 2 IBC's in half and have 4 X 500 mm deep grow beds,that way you have the 1:1 minimum filtration.Up to you.

So,IMO,you will need to build it up to 2000 litres grow bed ASAP.with a view to increasing your grow beds later.

From what I have read, 40 fish per IBC seems a good start,growing them out to 500 grams or plate size.

I can't stress this enough,you MUST have a good test kit to test at least daily when cycling and a thermometer to read your fish tank temp taken at the same time as your water tests.I suggest you test daily and post the results daily,I found people helped me out when I didn't know what I was doing.

Media, I suppose the cheapest media to use is gravel,be careful it does not have a high content of lime stone.also blue gravel is sometimes used.I use cottage blend river pebbles basically for the colour,plus rounded stones are not sharp on your hands and plants,size of the gravel ,I use 20mm or 3/4"
You can also use expanded clay,(Hydroten,Canna,)available from hydroponics shops, very nice,but way expensive in my book. I payed 30.00 for about 40 litres for one bag. some people also use scoria.That's about all I can think of.others might like to add.

I have my systems being pumped from the fish tank to the grow bed and returning,with my barra system It turns on and off by timer and the tank goes down about 1/3,then fills,the fish are fine with that,I just have an overflow to a separate tank just in case.

Just a few guidelines that I would and do use, but as I always say,it's up to you.

Good luck,show us some pics and let's know how you went.

Cheers.

[Yabbies4me]

Hey Mick,

Speaking from experience, if you start with 40 Murray cod in an IBC you will end up with one fat one. I started with 6 Murray's in 600Ltr's and ended up with one big girl. I even put mallee roots and terra cotta pipes in for them to hide from each other.

They were all identical in size when they went in, but from day one she grew at twice the rate of the rest, I don't know how true it is but I was told that the bigger ones exude a hormone that slows the growth rate of the others, may explain why there's only one Murray per snag in a river system.

[Daryl]

If you are going to run Murray Cod put them in the return tank and have nothing else but fish in the tank, If you give them hides it will just encourage there territorial behavior and keep them crowded and well feed and never live food, I have seen commercial set ups that run 180kg of fish per cubic mt of water which helps prevent cannibalism, but takes huge filtration and pure oxygen injection and when something goes wrong its fast and really bad, but they are a cool fish !

and every one should have a test kit before they have fish !