Is one IBC enough?

[John E Windsor]

I am almost ready to start building my system. My question is, will one IBC (with the top cut off, the top to be used as a grow bed) used as the fish tank be large enough to supply all of the grow areas? I am thinking about having two IBC media grow beds, to filter the solids. The media beds will drain into a sump tank and from there I want to supply 80-112 sq. ft. of DWC. Then from the DWC beds the return can be pumped back into the fish tank.

I am sure I am not the 1st new aquapon to ask this question, but somebody told me long ago there are no stupid questions. Increasing the fish density is my 1st thought, but I don't want to over do it.

Thanks!

[TCLynx]

And of course with today's gas prices, picking up an IBC from only 3 miles away could save more than $30 depending on where you live!!!!!  (especially in my truck!)

[John E Windsor]

Good question Peter and I am sure you will get some good answers.

It is my understanding that the media bed drains into a sump tank. So the sump tank water level will always fluctuate. Then the DWC (raft bed) is supplied from the sump tank. The flow into the DWC is controlled to allow a constant flow without causing a fluctuation in the water level. As in the diagram, the water is pumped out of the DWC and back into the system. The trick would be to balance the flow into the DWC to match what the pump is removing.

Now let's see if the experienced aquapons agree with what I understood to be the MO.

[Jon Parr]

Not quite, John. The flow is gravity from FT to media to swirl filter to raft. The raft inflow would be as constant as the pump removes the water, except the media is allowed to flood and drain (by way of siphon). The flood portion would allow the raft to drop water a bit, and the drain would allow it to replenish. What Peter is asking is if the drain causes a surge that may be problematic in the raft. Trying to add some kind of regulated flow valve between the media and the raft would not be practical, as a clog or restriction would result in an overflow somewhere along the line. 
Peter, I'd love to answer your question, but I don't know the answer. If nobody chimes in, you could test it in one of your outdoor lettuce rafts by filling a 50 gal barrel with inflow water and then opening a drain valve and see what happens. I know, that's no help is it?

[Jon Parr]

John, I just reread your comment. You described a way to do it, but there is no sump in the diagram. Basically, when the pump is in the raft, the raft is the sump. The low spot in the diagram between media and polisher is not a sump, bit a hard pipe feeding the polisher from the bottom (or at least mid-level). The set-up you described would work if two pumps were placed in the sump, one feeding the FT/media and the other feeding the polisher/raft. I think that's called a CHOP setup. I think. Too many acronyms for my brain. 

[TCLynx]

I would guess that the diagram might experience some issues with the siphon breaking if there is no air gap between the drain on the bed and the outlet in the polisher.  The amount the surge would be a problem would be mitigated by the type/size of the polisher. but I know of set ups that let the media bed feed directly to the raft beds, I would recommend asking some one who is running rafts after siphon beds to see if they find the surge to be a problem and how they deal with it.

The water level in the raft would fluctuate some but the exact amount of fluctuation would depend on the size of the media bed in relation to the raft beds.

I would probably also recommend the addition of a sump to the system (a clean water sump) that is fed from the media beds and the pump could feed to the fish tank at the same time as feeding to the raft beds.  If one wanted to add a polisher in line before the raft it would be easy enough but probably not necessary.  If one wanted to to timed flood and drain they could simply use a separate pump for the constant small flow to the raft bed and put the pump that feeds the fish tank and grow bed on a timer.

Contact me if you are interested in making it more complex and getting a constant out flow from the media beds doing timed flood and drain using sequencing valves.  this can be done but I'm not about to explain it in one paragraph.

[John E Windsor]

We found a good deal on IBC totes here locally. They were used for molasses. What a sweet deal! Clean and delivered for $70 each.

[John E Windsor]

Almost too nice to cut.

[TCLynx]

Oh boy that is a sweet deal, in more ways than one!!!!!

good score!