Backyard Aquaponics
A place to discuss aquaponics

I'm about to start my IBC setup up the back. I'm going to cut the top third off each IBC, and filp it over and suspend it inside the same frame (like a few others have done).

I'm undecided whether I should keep each one isolated, and simply pump from the tank below straight up into the GB. It might be safe to keep each one isolated, but this would also mean multiple pumps and no CHIFT PIST.

The other option (and the one I would prefer) is to use a sump and single pump to multiple IBCs. The IBCs would overflow into the ST and then pumped into the GBS. The question is how do I calculate how big a sump I need. I have one spare 500L tank - how many IBCs could that support?

Calculate the total amount of water you expect to be in the growbeds if they are all full then add some more for the pump to sit in.

For example 3 grow beds that hold 200 litres each would mean 600 litres, plus another 150 for the pump = 750 litre sump.

You can get away with a smaller sump if you alternate your pumping to the different grow beds.

Am I reading that you intend to overflow the IBC fish tanks into the sump then pump from the sump to the grow beds?

Is there any way to pump each IBC sequentially? i.e. pump to one IBC, then start pumping to the next and so on?

There is a HEAP of information about ppl pioneering the "sequential" fill.
Do a search.

You should realy read through a few of the established systems[ granted they may take days but you will see where others have gone wrong or got it right ]

After some deliberation, I've decided to not go with the CHIFT PIST and ST setup.

Instead, I'll simply use a small pump in each unit. This keeps it all very simple, each IBC is isolated, and it saves a fair bit of effort.

I figured that each GB will be about 250L, and the FT will be about 650L. Hence, only about 100L of water will be in the GB at peak, which won't drop the water level in the FT by too much anyway.

The question I have is, how many SPs would each IBC support? I assume the size of GB will be the bottleneck - correct?

Once a system is established (cycled) you can support about 3 kg of fish (grown out size) per 100 l of grow bed. How big do people usually grow out silvers to?

Well if you plan to grow the silvers out to 500 g then you could have about 15 fish in a tank that was filtered by 250 l of grow bed.


Back when you were contemplating the CHIFT PIST some one said to make your sump equal to all your grow bed's volume. That is not quite necessary. You want your sump tank to be able to hold more than all the water needed to flood all your grow beds. So if it takes around 40% of the volume of a grow bed to flood it, then you want your sump tank to be 50-60% of the total volume of all your grow beds. (the extra % gives depth for the pump to operate as well as some extra depth to deal with topping up or evaporation or to install a float top up valve above the pump run dry height and below the usual low water level in the sump (makes topping up automatic.)
Another note I would suggest about CHIST PIST, pump from sump to the fish tanks, have the fish tanks overflow directly into the grow beds and the grow beds can drain into the sump. If you let the fish tanks flow to the sump, you get solids in your sump and have to clean it and the pump more often.

Based on what I am reading here about your system, you will be way under filtered if you want to stock lots of fish. Having equal volume of grow beds to fish tank is often a good starting point and many people who want lots of fish will go for twice as much grow bed volume as fish tank. (For twice as much volume as fish tank, you will probably want a sump tank/s equal in volume to the fish tank/s.

Good Luck, do lots of reading as others have suggested, It may save you lots of effort.