Backyard Aquaponics
A place to discuss aquaponics

I've been wanting to do an IBC system for a while, so here goes!

Decided on a low energy setup after reading Jimbo and Blythe's threads. Thanks for the pioneering work, guys. Can see the advantage to running off minimal energy, intend to go solar in time.

I'm working on a design for growbeds that can be easily switched between aquaponics and hydroponics for flowering. My friend doesn't believe it's possible to grow orchids with fish - challenge accepted.

The aquaponic system will be constant flood, circulating by airlift from fishtank to growbed(s) and back via return pipes. To go hydro, I'll shout "Autobots, transform and roll out!" then stop the water flow to the bed and close the return pipe valve. The air pump will be switched from the airlift to airstones in the growbeds. Guess I'll need to run an airstone in the fishtank too, luckily my airpump has multiple outlets.

I've drawn a simple diagram, a close-up of a growbed above with the overall system below. Growbeds will be cut to about 30 cm. depth and placed into the IBC metal pallet, supported on cinder blocks (not pictured). Halved sewer (or thicker, drilled) pipe along the bottom of the GBs will keep the media (crushed rock probably) off the drain pipe and airstones. I want the airstones accessible by removing the IBC cap, so they can be checked and replaced. I intend to have the return pipe lead straight back into the IBC valve to avoid piercing the fish tank.

OK, so this system is still theoretical. Before I get to angle grinding I'd appreciate some feedback, especially about the practicalities of working with IBCs and airlift systems. I also have some questions it'd be good to resolve first:

1) Will these ~30 cm. growbeds be deep enough? I was wondering if there was a reason people were using those big 1/2 IBCs.

2) Is going through the caps workable to get a removable yet leakproof fitting? I imagine I'll use some kind of flanges on both sides of the cap, flanges that can be loosened around the drain pipe when the cap needs to be removed.

3) Is sending the return pipe through the IBC bottom valve a good idea? People have mentioned angling the return pipe for better oxygen circulation, but I can't see as there'll be enough pressure to get much surface turbulence...

4) As I'll be slicing off the top third or so of my fishtanks, is there a good way to block them against light? I was thinking of some kind of hinged lid, but it'll need to clear the airlift. Could go with cut plastic, but I'd like to make the systems presentable.

5) What's the easiest way to automatically maintain the water level? I figure this is a big deal with the airlift being so sensitive to head. Jimbo said he uses an auto fill-thing for watering cattle, and there was talk of a ping-pong ball in a pipe... A party trick or some kind of float valve?

Am I understanding that in order to get to your airstones and drain, you'll have to drain the beds and unscrew the cap in the bottom? This sounds like a bad idea. Why not just let your standpipe go to the surface? Also, 2 more pipes you can drop your airstones in.

Also, there'd be no good way to dictate the height of your growbed if it's a drain instead of a standpipe. You'd have to try to balance the flow and that's bound to give you trouble.

1) 30 cm is fairly standard depth for growbeds. I just figured since I was cutting the IBC I might as well make it deeper for nothing more than the cost of growbed media. I did this because some have reported less of a need for cleaning out growbeds with deeper growbeds. It seemed to make sense to have extra filtering capability.
2) Both my tanks had a solid cap without the 2" bung in them.
3) If you return water at the very bottom and then pull it out with a SLO at the very bottom, you may not circulate the water in the tank properly and you bypass most of the FT just running a loop through the GBs. I plumbed mine through the wall of the tank and turned it straight up to the surface where the return pipe stops just 1 mm below the surface. Its not a great flow coming out of a 3" pipe but it sure makes the water dance.
4) Maybe leave part of the lid fixed and the airlift comes through it, then hinge the other portion.
5) My stock tank auto fill works great. Made by a company called DARE. However it has an aluminum housing and metal in the fish tank ain't great. So, if you can find a plastic stock tank filler, I would recommend use that.
I would reccomend a sleeve above your drain to access it. Draining a growbed to investigate a problem over and over may get tiresome. On that thought, could you use the bottom half of the IBCs for your growbeds, with your halved-pipes running from the ball-valve across the tank?
The valve outlet could be your drain and shutoff and if pipes disconnected from the valve could access your airstones that way. That might not work...
As far as dictating the height of the water in the growbed, its regulated by the height of what ever you use to fill the fish tank(like the stock tank auto fill I use-or the ping pong ball in a pvc adapter thing). The water height stays constant through the whole system. Using a standpipe may encourage crud buildup in the bottom of the growbeds.

Brilliant, thanks guys. Feedback and answers help a lot.

kthignight24, what Jimbo said about the water level. It's like it's all one big tank. It's true the cap solution sucks, but it beats digging up the beds. Putting airstones down vertical pipes seems a good idea, but I wonder if the air won't bubble straight up and out without properly diffusing?

Jimbo, please explain what you mean by a sleeve above the drain for access? I don't know what a sleeve is, or how it would connect. But using the IBC bottoms is just as good and saves cutting the metal liner. My airstones do just fit through the IBC valve, now I'm considering ways I could extract them and connect the airtubes. The tricky bit is the IBC valve needs to be closeable, so I can't run airtubes or "airstone extraction strings" directly through it. But maybe through a hole drilled just behind the valve...

I've had the idea of skipping airstones, instead using small airlifts in the growbeds to oxygenate. Airlifts won't require maintenance or protection against the weight of rock. I did a test with an airlift I put together out of scrap piping and plastic. At a depth of 30 cm. and with one airtube connected, it lifts a blob of water about 8 cm. every second. How do you guys think this airlift oxygenation would compare with an airstone? Unfortunately I don't have a dissolved oxygen meter to test it.

Extracting through the valve would require removing pipes and using coathangers and I was typing that while it was too late. I should really stay off the forum after midnight.
I meant a sleeve like around a standpipe. Just a vertical piece of pipe big enough to stick your hand in to reach down to the drain. Maybe even incorporate it into your airstone tunnel to access the airstones.

Yes of course about the water level. I'm not used to looking at 0 head systems yet . Drop an airstone into water and you basically have an airlift. The air circulates the water from bottom to top, thus aerating it. If you put a pipe around the airstone, you increase the effectiveness of the circulation. I would think this would work great in a growbed. You want the air to move the water up and either from the center to the outside or the other way around. Keep the picks coming!

OK, project was on hold for a while due to Reasons. Time to crack on!

I've had a think about access to airstones in the growbed, and come up with the idea of a U-shaped pipe. I'll make it from standard sewer pipe (about 110 mm. diameter this side) between two elbows. A U-shape basically, with the airstones in a drilled length of sewer pipe between two elbows; air tubes down one elbow, and plastic line to extract the stones down the other elbow. I'll cap the tops as I worry about the oxygen diffusing into the atmosphere instead of the water.

Simple plan but hard to explain, should make more sense with the picture. Also shown is the sewer pipe I'll be using. I can't see any reason why this won't work? Seems to solve all the issues of previous designs, but please shout if you see a problem.

Looks good to me, just make sure the sewer pipe isn't made out of a plastic that will leech. I buy 4" HDPE (milk jug plastic) drainage pipe at the local hardware store. Another thing is I've heard that air stones clog eventually and need cleaning. In Jimbo's thread he discovered that his airlift worked BETTER when he omitted the airstones and just had 4 tubes coming from his pump. One idea is to get rid of the airstones, pump your sewer pipe full of air and just let it diffuse out of the holes you drill in the pipe. Less maintenance, more (?) circulation. One final thought. Since your growbeds will tend to capture solids, over time they may collect either in your sewer pipe or above it (possible clogging the holes). Just something to watch out for... they may need a cleaning after a while.

Ah, thanks kthignight24!

I'll have to check what type of plastic the sewer pipe is, probably PVC. The rest of the plumbing will be irrigation fittings and pipes.

Yeah, the stones do clog, I've seen that from using them in aquariums. That's why I need a way to replace them without too much hassle. I remember the bit in Jimbo's thread where the airlift works better without stones, I'll definitely copy that design. I think the reason is airstones add back-pressure, so less air gets pumped into the column. But I think finer bubbles will be better for the plant roots... My design is based on a lot of thumbsucks, but that can't be helped without the proper measuring equipment.

Also true about the holes getting clogged. That's a tricky one to solve. Keeping algae at a minimum should help - the fish tank will be well covered against light, but do you think a 3 cm. layer of gravel above the water line in the grow beds will be enough to stop algae growth? I can also put mesh filters on the end of the water outlets to the growbeds, occasionally cleaning those will be simple enough.

Oh yes, I've cut my 1st IBC and will probably have it up and running in a few days, pictures to follow then.

One Question.. why are you do you want to aerate the water in the grow bed..?

To me it seems to be a Waste of effort and material's..
Why not have a Flood and Drain on the system and do it that way.. Even a F/D if it only does Partial drains will work fine..

I have one Growbed in my system that due to tight factor of the Lid on the Root guards partially drains the Growbed once the water is flowing out of the drain pipe..

Juergen

What is going to force the air out of the holes you drill instead of just coming out of the U parts of the pipe? Looks to me you will have to have a way to trap the air in the middle of the U or it will just run to the sides.

Ditto what helomech said.
And, My airstones were restrictive but also I was working at twice the depth. You may get a lot more flow at less depth/pressure.

SnowT, I couldn't figure how to do Flood & Drain with an airlift. Maybe it's simple but I'm not clever about siphons. If there's a way to do F&D for my current or next IBC airlift setup, I'd like to know.

helomech, yeah that's a good question. I have end caps for the pipe, hoping those are airtight enough that air pressure forces the bubbles out the drilled pipe. I will test it soon.

As for progress, I've plumbed everything and tested the lift - basically done. Only prob is the earth beneath the FT has settled a lot with the weight of water. FT is a few inches not-level which increases the head so decreases flow rate. Emptying all the water to fix it is a pain in the ass. Planning to use a siphon tube but working on a way to hold it in place so I don't have to stand there getting my shoes wet for 10 hours.

You actually don't need additional aeration in the GB. I run mine CF (constant flood) and constantly flowing and my plants do just fine. It's up to you, but the extra complication may not be worth it.

Sure kthignight24, what I'm testing is if I can isolate the GB. In other words, stop all flow between FT & GB. If so, I can add stuff like fertilisers and pesticides to the GB without killing fish.

I'm about done, just waiting for silicone to dry (a problem happened) before adding gravel. Airlift kicks ass, bubbles flow through U-pipe well; I reckon it'll all work as intended.

Lesson learnt: building heavy stuff on soil is all kinds of trouble without some kind of foundation.