Backyard Aquaponics
A place to discuss aquaponics

Ok, maybe now's the time to start getting feedback on my ideas so far ...

I've already explained what I'm after here: 3rd last post
and GD replied here: scroll down again

What I'm currently thinking is getting 2 large & cheap plastic crates ($2 dollar shop maybe?) and lining them with a fish/people safe liner. I'll have to look around to get the best size possible, but say 45 x 65 x 30cms.

Putting 4 yabbies in one, keeping the other in reserve for when the yabbies grow bigger.

Finding or making some sort of basket (metal wardrobe baskets?) which I'd line with mesh, put in pebbles and hang into the water. Ideally, 10cm deep. As I've got a little kid, I'd paddlock the mesh basket thingy to the plastic, but have a key myself so I can lift to feed. I'd probably start with bok choy growing, then see if tomatoes / capsicum etc can work.

What I'm hoping for, is that with low stocking levels and a pretty hardy type of animal, I can get away without pumps, filters etc. I'm happy to run an airstone if the yabbies don't wreck it ... I guess if I had to, I'd investigate the cheap Dick Smith solar options for filters / pumps ...

What's inspiring me is the floating raft things I've seen in some photos (can't quite recall where, now) and the fact that when I had a bathtub koi pond, filter/pump sellers said I didn't really need filters/pumps, as I had some plants and my stocking density was so low. (Both bathtub & koi are no longer, unfortunately).

I'm not aiming for optimal yield / growth rates ... cheapness, portability and experimentation are more important to me. Oh, and GD, your suggestions would probably work far better than what I'm thinking, but I truely can't get 78cm through the front door, I've measured

What do you guys reckon - workable? mad?

so you want to just hang the basket into the water (in which the plant will gorw?... I'm wondering about DO levels.... roots still need significant amounts of oxygen in the water...

The air pump would look after the DO levels - I would be more concerned with:

- build up of solids within the tank as there is no mechanical filtration. This would be a pain because you would need to vacuum the bottom of the tank regularly
- sustaining a colony of bacteria (Nitrosomonas and Nitrobacter). Although they would colonise on the roots, the basket and the tank, this would be far from optimal and when plants are removed you will lose any bacteria on the roots
- rusting of the basket. This will happen I guarantee it.

I know you are talking small, but I reckon you would be better off getting a really cheap aquarium second hand, putting a cheap container on top with clay balls and running continuous flow through a grid on the balls. This would necessitate a pump, but it would only have to be a small one (which converts to cheap) and if you set it up right this will also handle the aeration.

or perhaps try the air driven flowerpot filter I use in a school aquarium.

(see video -

http://s99.photobucket.com/albums/l313/ ... h=imgAnch6

or an airlift tube if the basket is sitting right ontop of the tank/in the water...

Hmm, how do you protect air stones from yabbies?

Also, the solids ... what sort of problems do they cause? Do I really need to remove them?

I am thinking plants hanging directly over the water - 2 reasons; it will prevent baby's access to water & drowning and also, it will make the most of limited growing space, I have other (soil) plants I am/want to grow in my rare sunny areas.

I'm not thinking of running this continuously - grow 1 bunch of yabbies up, eat everything, start again from scratch but with a bottle of used water. Rusting, yes it's likely, I could look at plastics if you think it will happen in less than the time it takes to grow a yabbie to edible size?

I'm planning on running this system 1 year max, as a trial, then building a completely new and bigger one if the trial goes well.

yabbies tend not to mind alot of crap at the bottom, but as VB said, DO will become more of a problem as solids rise, but then i think yabbies are fairly tolerant of that too.

Missed the bit where rusting was mentioned, but i remember reading somewhere not to use bore water hgih in iron, so rusting may be a BIG problem. As suggested, get a cheap ass aquarium.

would seem that and dissolved metals are problomatic for the poor yabbies!

Hey RS, I have yabbies and marron and haven't had any issues with my air stones at all (yet anyway). I did however have a couple of air curtains (which are essentially just a foam tube with holes in it) and both of them were destroyed by my marron in a matter of days. Pity I threw them out otherwise I would have posted a pic for you, they tore massive holes in the foam. Ive seen them sitting right on the airstone and picking at it, but they haven't done any damage to them.

yeh they don't taste to good! air stones that is.
If there is no flavour they wont attack.Square bear involved.
C1

If the air stone is put in a flower pot filter, the yabbies wn't mess with them.

If te flower pot filter has a mix of gravel and maybe an old nylon sock, you will get good filtration.

(The Cichlid water in the video is changed 50 % weekly. The flower pot filter realy polishes the water. The gravel is rinsed in rainwater and sock lightly washed in rainwater fortnightly - notics .. I used the word lightly, because I want to keep residual bacteria in the system.


I managed a dozen yabbies in a small tank doing this , and curently am rearing nearly 100 tilapia fry using a flower pot , air lift filter ..

The filter works good, but if you don't have plants to get rid of the nitogen based waste ... then you will have to do frequent water changes, and I think yabbies don't like chlorine too much, so you would need to condition the new water before you do the water changes. (I used to do this by leaving tap water in a wheelie bin for a day or two with an air pump bubbling into it.

In one of my flood and drain buckets I have added a sock filled with sand and gravel.. just to have a reservoir of good bacteria. I NEVER clean it! Just leave it there.

Thanks for the info ... right, metals bad (pity, I was thinking today how easily I could get food grade metal stuff) but air stones, possibly airlift pumps (if I can build it right) are ok.

D'you reckon yabbies would make a hole in thick denim or canvas fabric? It occured to me that's an easy way to hold plants, if not. And for some (prolly silly reason) I'm not as worried by non-food grade fabric as I am by non-food grade plastic.

Let me know if I'm being really silly 'tho, won't you?

Oh, and I verified the local pet shop has misc. 4cm yabbies today ... how long do they take to grow to edible size?

RedS,
Have you purchased THE BOOK yet ????

Muzza

Nup. I'm planning on asking relatives to club in & buy it for me for Christmas

Ok, I've been doing more thinking about the materials I might use. In particular, I am trying to use materials I already know & understand how they work. So, anyone know of any issues with these (for me, toxicity, or for the yabbies):

*canvas, denim, other fabrics?
*house bricks, with some render still stuck on them?
*woods incl. bamboo (yes, clearly mdf is pretty toxic)?

Thanks!