Backyard Aquaponics
A place to discuss aquaponics

I think the problem is keeping the oxygen levels at saturation.

The UVI research talks about appropriate spacing and Ryan has mentioned it to. Once I get my O2 meter I'll be able to let people know.

my constant flow bed is going gangbusters

So is mine, aside from the fact I put in red cabbages when I thought I was buying beetroot seedlings.

Stuart I was not joking when I said airlift assisted internal circulation; its in a spa which had a number of difficulties in ensuring that water would flow through it properly, shape seating sheer depth.
I am not normally in favour of air pumps but this was one of the exceptions.

Hang on I thought that was for your DWC?

Its got about 800l of bottle caps in it.
DWC will be in my new system (but it's a bit of a Charlie atm).

We have all seen the comparisons that EB did so I'm not saying it doesn't work. Like I said I think they might be sized limited unless you add aeration or something.

If it isn't low dissolved O2 in my one does anyone else have any suggestions as to why it is under performing? Colum has already suggested channeling but if that were true I would expect that either end of the bed would be doing well instead of just the inlet.

Gently pull a plant from each bed (well more dig it out) and check the root system. CF in Joel's test was the leader until the end when F&D was slightly better.

You may have to investigate the reason further i think.
Maybe dirty?
maybe you didnt clean the rocks on that bed at all and the bottom few inches is blocked up.

is that bed after others?

just throwing ideas out there.

Me clean gravel you must be joking. Besides even if I wanted to 24kL would have put me off.

No the bed is not after others. I have two beds both fed constantly from the FT. I haven't measured the flow but I know the constant flood is getting more flow.

I got both CF and F&D systems growing tomatoes atm.. both seems to be growing identical... u may have a problem of lack of aeration in CF.. of overly excessive decaying matter in your CF which will lead to increased BOD in GB.. or too much organic carbon bacteria in your CF due to solids etc... these bacteria can actually compete with plants for the same nutrients... VOC usually is a no no in aquaponics systems because it leads to POA formation which will lockout these nutrients from your plants.

pics of my CF.






my F&D SYSTEM




FYI my CF gravel range 3/4'' to 2'' sizes.. so very big pore spaces.. also I filter the water extremely before it enters the beds at 10 different entry points... CF can be a pain to manage at times... but it has the same amount of surface area as a F&D with the benefits of a DWC... without the drawbacks of plants weight limitations found in floating raft systems.

Ok you got me there. What is VOC and POA?

MY bad.. meant to say PAO'S phosphorous accumulating organism... and Voc volitite organic compounds

Volatile?

thats the word... these texts too close

Yeah, I was lost with those too.

One thing I noted about Joel's systems, they have the inlets spread around the whole bed with PVC tubing with holes in it? So it's evenly spread through the whole system.

I wanted to have a play with a DO probe, to see what my levels are in the constant flood/DWC, but it seems expensive for a few simple tests. I'm currently replacing all the 40mm gravity fed pipes with 90mm pipes, so I can increase the flow through the beds (it's quite slow atm, because any faster will make the beds overflow), I'm hoping that'll give it better growth.