Backyard Aquaponics
A place to discuss aquaponics

i have today set up almost completely a new continual flow system running 500 litres and 3 sixty litre grow beds filled with clay balls. I have read the book and in it you say that you set up the pipes to feed your grow beds approximately 30cm apart. Mine are less than this far apart and it seems like they only wet the section of the gravel directly under the holes.

Do you have any suggestions on how to fix this apart from more pipe and do i neccessarily need to fix this. Should I instead just plant the plants closer to the holes. also i recognise that the ability of these grow beds to filter and remove the waste is limited but the plan is to start with this and then add an NFT system to grow lettuce, tomatoes, chilli's and herbs. Any comments are appreciated.

Hey Nick, nice set up mate...
How did you cut the tank, did you use an angle grinder?
You have a couple of choices with your water distribution on the grow bed. You could leave it as it is and plant your plants near the irrigation tubes, as the roots of the plants grow, the water will be forced through other areas of the gravel beds.. Thing seem to get better over time, but there will always be the odd dry bit.

Personally I would look at playing with an automated syphon on the outlets of the grow beds, which will cause them to flood and drain, you should only need three elbows and a little more pipe.. Elbow pointing up, piece of pipe then up to just below gravel level, two more elbows to form the bend at the top, with the last bit of pipe pointing down towards the water....

Damn if I was at home at the moment I'd draw a quick diagram and post it... If you check out the second picture in the barrelponics thread, here, you'll see Dan has made a similar syphon by using a loop of smaller diameter pipe...

Nice idea with the tank cut in half, can you still use the other half for another system?

the tank was cut with a circular saw with a grinding blade. Very quick and easy. the other half is at a mates place with marine corals in it. but i was more thinking along the line of using it as a large conttinual flow grow bed. i can get whole tubs at work for $120, meaning $60 for each bed. won't last as long as the beautiful grow beds made by murray but will do for a year or two.

Also is there any reason you prefer the flood and drain method to your original continual flow system. the continual flow to me, theoretically, works better in the culturing of the bacteria needed for plant growth. the problem i see with the flood and drain in the none pump controlled method is that the timing could be a major issue.

flood and drain in hydropnics has extended drain times. for example at night in warm clients they have two to three hour empty periods to really get the roots dry and aerated.

with the automated pipe system as soon as the water drops to a level where the suction/seal no longer exists the flood cycle starts again. this will not give the roots, in my knowledge, enough dry time and you may run into rotting issues. i hope i am wrong because it would be a very effective and simple system.

With the continuous flow, the water is continually flowing over the roots, so if anything the roots aren't getting any 'dry time'.

I don't know.... Wilson Lennard just finished his PhD thesis on aquaponics and found continuous flow to work better than flood and drain in his experiments. Personally I have had great growth rates from both methods, but I've found that for me, flood and drain requires less maintenance in cleaning the gravel growbeds etc, and no problems with dry spots....

My large flood and drain system has been going for over 2 years now and I've had no major problems and good plant growth... I think it's a matter of situation, design constraints and personal preference... Some people like ford, some like holden, each thinks that one is better than the other for valid reasons... Where as I drive a toyota....

Will the brown stuff settle out eventually? Should you wash the pebbles first?

Hi Nick Great simple setup What kind of fish are you going to get? I can see you have some duckweed already happening. Post some more pics when you plant the growbeds.

the brown stuff was ettling out but I decided i did not want it in the system so this afternoon i emptied it all out and gave it a good wash. The bown dust had begun to settle out as there was a layer at the bottom that required a hose and scrub to remove. yes I should have washed the clay balls before putting into the system but was to keen to see it set up fully.

I got 30 silver perch from a pet shop this afternoon for $21 so was happy with that price. Would of liked to put muray cod in there but the perch were simple and local so will add the cod later once established. I also have a 300w jaeger eheim heater in there that should be able to keep the temp constant until summer comes. So groth should be good.

Hi Nick

Jeez those fish were cheap - do they have more? Can you let me know what pet shop you got them from. Re the system, my tiny test setup is working on continuous flow and has poly pipe like yours running at 4 or 5 cm below the gravel (which I think helps to distribute the water). Only problem with this sort of setup is that the holdes in the pipe are quite small and are getting easilly clogged with crap. As soon as I get my bigger grow-bed, I will convert to flood and drain.

the fish are form stafford pet super store and yeah they seemed to have heaps as they use them for feeder fish for larger predatory fish. i will have to wait and see on the continual flow system and see how we go.

Regards flood and drain and recirculating systems....

In the past I have tried nutrient film technique using an organic hydroponic solution I concocted from a mix of manures with a little wood ash thrown in.

No growing media, just highly airated nutrient solution.

I had no root rot at all.

At the moment I have my plant roots dangling in my fish tank wheelie bins. - I have real good airation. Again . no root rot at all.

That's interesting that they would be using silver perch as feeder fish. I wonder if the quality would be any lower than those bought from a fish farm. You never know, they may be hardier as pet shops don't usually treat their feeder fish very well. On the other hand, disease issues may be higher???

They must just have a very cheap supply....... Does seem very cheap... I don't imagine that they would be very different to stock from elsewhere...

ON the roots in water issue, I was just looking at my continuous flow system a minute ago, and there is a puddle of water sitting around the root ball of the tomato plant growing in the system. It's sitting in water 24/7 and looking fairly health at the moment....