Backyard Aquaponics
A place to discuss aquaponics

Hello,

After I posted my system here: viewtopic.php?f=13&t=27490

I have got lots of helpful do's and don't do's.
Beside I have changed almost complete my plans for a commercial system I have used my trial system more efficient (and changed many things over and over again)

The pipe system shown in above mentioned link will disappear by the next chance.
Pipes are too much trouble with balance, heat, clogging by roots, don't excuse almost no pump failure and they limit my experiments.

I will change them to deep-water grow beds and here comes my question:

Has anyone tried to raise red claw crayfish under his rafts in Deep water grow beds?

I have thrown some styrofoam sheets directly into the yabby tanks and have the feeling the yabbies are doing a very good job.
After now 1 year the plants were growing faster and the roots were well "maintained' by the Crayfish. All black roots were proper clipped and the white roots were not damaged at all.

This brought me to the idea that it might be possible to make wider and longer grow beds (to grow better sizes of Crays) and having beside more space hundreds of free helpers for healthy plants directly in the grow beds.

The following points I have already considered and made some ideas:
- Crayfish fry is tiny and you will find the crays later in every part of your system. Here helps 50my hydraulic
filter mesh.
- Catching and harvest as you cant take all time the rafts out. Traps are here a solution
- The Yabbies eating roots.. Not as far I could see till now, they were very picky and ate only black roots.
- the poo will create root rot over the time. here you need to make your grow beds with a slope and in the
center of the slope you put a pipe with holes like starting with a 5" pipe and all 2 meters you reduce the
diameter. Towards the bottom you drill 5mm holes (big enough to suck the cray poo through) lets say all 5 cm... see below drawing.



5mm holes are big enough to catch out the solids that collect tin the center of the slope and also the fry will hide inside. This way you control also the equality of your size and the amount stocked.

The hides need to be arranged that they not block the solids moving to the center of the slope, this can be achieved by arrange them proper and let the current do the job. The homes can work as nozzles as well and create a slight jet stream.



So and with these plans I will try to make a test grow bed.
But it would be nice to know if ever anyone had yabbies in his grow beds and what went right and what went wrong?

Cheers

>> But it would be nice to know if ever anyone had yabbies in his grow beds and what went right and what went wrong?

yabbies or red claw - two different types of crayfish.
Cherax destructor versus Cherax quadricarinatus

However the answer is it depends (as always). In cases they will eat at the roots and run amok, in a deeper setup they will probably be OK - depends on how hungry and bored they are. One option is to have a mesh between the plants and the crayfish - but you would need a deep DWC system to do that.

Their babies would love hiding in the roots <- definitely yabbies.
But then yabbies do not have the sub-species name 'destructor' for nothing.
If they go destructor then you will get quite a lot of veg matter.

> Crayfish fry is tiny and you will find the crays later in every part of your system. Here helps 50my hydraulic
filter mesh.

yep, they will love it.

> The Yabbies eating roots.. Not as far I could see till now, they were very picky and ate only black roots.

as above, a deeper DWC would help.
Red Claw are less aggressive and less destructive.

> the poo will create root rot over the time. here you need to make your grow beds with a slope and in the
center of the slope you put a pipe with holes like starting with a 5" pipe and all 2 meters you reduce the
diameter. Towards the bottom you drill 5mm holes (big enough to suck the cray poo through) lets say all 5 cm

It wont be a problem, so dont need to worry.
I use yabbies (as in Yabbies) to keep my fish tanks clean.
If you have good circulation and flow through the beds their waste wont be an issue.
And if they die their mates will eat them anyway...

Thanks Darren,

the last point was for me a major issue.

If I have a good flow through the poo will be carried away sounds good.
With 50my hydraulic mesh there is nothing going through.
Drum filters are equipped with that and if I want to control the system I have to get the fry also under control so it looks a drum filter might be the way to go.

In a big system as we are planning we certainly want to collect the solids as they have approved to be the best fertilizer I have even seen.

There comes already with 4 fish-tanks a lot together, so it creates a small side income to sell high end fertilizer to Hotel gardens and households.

I mean Red Claw Crayfish, they are what we got.
Before the 'C. destructors' massacred themselves in mass even they got fed 3 times a day.

The Red Claws behave great in the roots and the plants were growing better.

The DWC system is by now planned to be 60 cm (55 cm water level) deep, but if the water isn't an issue for the ratio I might even add another 20 cm in my drawings.
From my point of view more water is more easy to balance as well. I would probably end up instead 1:2,48 around 1: 2.65 (Water body Fish tank : grow beds)

Also the outside planned grow beds are partial planned for making greens for fish food hence quality isn't that much of an issue in those grow beds. We tried a lot recipes using herbs and other plants to see how we can increase the taste.
Carrots for example have a positive influence and garlic makes them eating as mad. They seem to love garlic..


Cheers for the info..