Backyard Aquaponics
A place to discuss aquaponics

Should see mine now - as of today it is uglier. Temps are dropping here and my current system has the tank outside. To try and get a little extra heat into it during the day, I have taped black plastic around the outside of the tank and also replaced the panda fabric that covers half of the tanks top with black stuff. Temps are goaing to be a real issue for me this winter - by next I will have my big system with tanks in shed and beds in greenhouse.

MMMmmm, interesting debate...

I am one of the biggest proponents of recirculating AP, and I peronally feel it's the best method of AP. But in terms of pure definitions of what AP is, then we have to consider the whole range of methods that are available.

Hydroponics has an enormous range of methods from recirculating to flow to waste. Aquaculture has an enormous range of methods, recurculating, flow through, cage systems etc., they are all aquaculture, but some methods are better than others.

See I think that if this thread is purely debating the definition of the term, then we have to look at it from the idea that it's "The use of plants to extract nutrients from fish water, and, using fish to supply the nutrients for plant growth via a soiless growing method."

Then we can get into the debate about which methods work best, are best proven, most reliable, most productive, best for the environment, most efficent, etc, but this is probably a seperate debate.. And a damn good one to get into....

It all comes down to what you want to achieve from your Aquaponics system. Use the resources you have and use them effectively to make a BAP system that works for YOUR backyard.

For me and many others it is to conserve power, reduce water consumption and extract as much nutrients from the water as possible. In a small footprint. If you had tropical fish (heated water) in a flow to waste system, not only are you losing heat, you are increasing your electricity usage to reheat the new water. Not to mention topping the water up.

Cold water flow to waste, if you don't consider water bills, flowing down through a series of growbeds where all the nutrients can be extracted is a good possibility and if most of Australia wasn't in drought it would be a good way to go for us. In fact I also have a flow to waste system, whenever I do water changes on my aquarium the water goes on the plants.... now is that still aquaponics?

Environmentally friendly - recirculating......
High stock density and ridiculous plant growth - flow to waste.

Nobody has given compelling reason why once through should use more water than recirculating. This seems to be a 'cultural assumption' with little grounding in fact. As I said in the other thread, theoretically (and yes, I know you all hate theory) demand driven irrigation should use less water and less energy. In general, optimal control theory says that goal function driven behaviour will outperform anything else.

And that was Angus Stewart's opinion on GA recently.

njh.... could you post some more pics of your smart valve - seedling pots area....




curious how you've set up the valves to service that number of plants.

Regarding ...



I set up a thread for people to post (hopefully honestly) their respective top up / usage figures....

Added a request to post tank size as well so that we could perhaps work out percentages and get some emperical data....

Could you post your figure there also.... particularly as you are one of the few who utilise the auto pot / satellite pot regime.

Here's a picture I've got handy:

[left]http://njhurst.com/garden/greenhouse/2007/small-IMG_1646.JPG[/left]

As you can see, it's a multideck AV plant stand that my wife had in the garage for years. I just went and measured it. It has 1.2m x 0.6m metal trays about 1cm deep (I needed to tape along one corner where this wasn't sufficient headroom to close the valve). Each layer holds 80 pots, so 240 pots all up. For a larger area I'd probably put some plastic film then carpet underlay down on say concrete area and put a single valve at the bottom of the hill. No idea the maximum safe number of shared plants for a watering area - will depend on things like pan evaporation, wind exposure, plant growth rate etc. The delivery rate is certainly higher than the usage on my plant decks.

A deck contains (empty) about 7l of water, and cycles maybe twice a day (14L).

The smart valves are under the red pavers.



I'd like to. I'll go and plug my tank waterlevel gauge in. Right, now to wire it up... The big problem is that my water is used for a) drip irrigation, b) open loop living wall, c) hand held hose use d) smartvalve, e) buckets of water and watering cans for pots. It is also a rainwater tank, I allow the level to cycle from 2kL to 4.5kL (but keep it at about 3.5kL from a larger external tank using a float valve).

However, I do know that it drops about 20cm a week in level without rain with the ball valve off. That's about 800l a week or 120l / day.

Cool Nathan... so the smart valve works just fine ....

i.e for those that may not know (correct me if I'm wrong)... the smart valve is designed to only open and refill (normally a pot) when all water has been used by the plant(s).....

... replenishing the trays once they're empty.

Great use of the technology... particularly for water sensitive plants

Can see some applications for myself there...

What are the smart valves worth on their own, as opposed to the autopots?

Yeah, as much I find the cost ($27 for a piece of injection moulded plastic) deplorable. I must take my hat off to their brilliant design (have a look when you get a chance, they are quite subtle - a bit like autosyphons). They don't run completely dry, they rely on the miniscus of the water to control refill, so there is a thin film of water in the bottom. But it is sufficient to control mossies.

The valves are $27, I also get a special cover for $5.5 that means I can park them under a brick to stop them floating (and staying jammed on . As I mentioned elsewhere, there is a discount for BYAPers who mention that is their use.

so what would happen if they stayed on njh?

they dont stay on not yet anyway

Well then I would water the ground underneath. Which is why I put a brick on them so that they don't float and stay on...

If you get the autopots they have a little peg which stops the valves from floating away. But I'm a cheapskate, and after seeing aeldric's ones I realised that I could just buy a few valves shared between lots of pots.

Indeed, considering the flow rate of 5mm pipe, I could probably irrigate 20m^2 with each smart valve. Essentially F&D irrigation without a return.

Edit: I should measure how much water thay are actually using. L says she thinks they are more like 1 cycle a week (1L/day tray). What I'll do is turn the valve off and see how long it takes to empty, then turn on to refill, turn off and time again. That should give a reasonable estimate of actual water use.

I guess this is half of how they work out the actual water needs for transpiration-growth for plants (5.5l / lettuce apparently). The other half would be to use a controlled environment to restrict evaporation.

"Biofertigation"

n. Using waste products from aquaculture to fertilize and irrigate planted areas.

Damn, it's taken already...

http://www.google.com/search?hl=en&safe ... tnG=Search

Hi Nathan,

Are you using fish tank water to irrigate your olives? If so, how do you keep the fish solids from blocking the smart valve?

Enlighten me if I seem to have missed something.

Gary

Olive pots Gary - not olives. Looks like Nathan has natives in the pots.

The big thing in favour of not blocking the smart valves may in fact be that my pump is about 40cm off the bottom of the tank. I remove solids separately using the simple venturi things we discussed ages ago.

I haven't had a blockage yet.

Not olives, natives as VB rightly says. The olive pots are square with nearly open bottoms (a coarse mesh) and so they sit together very neatly avoiding wasting space. Square pots make for better roots systems too.