Backyard Aquaponics
A place to discuss aquaponics

All around the web, many lengthy discussions are devoted to removing the pumps from aquaponics, or at least the pumping energy use. Everything from perpetual motion machines to bikes to water towers to windmills are tossed around.

However, what if one just had a large tank full of fish, with some raft type systems on top and a bubbler (which would use minimal energy, but aerate the system.) Then one could bucket out 5 percent or so of the water each day, pour it into the reservoirs of wicking buckets full of vegetables, and put fresh water back in, slowly so as not to shock the fish.

What would be the pros and cons of this?

Cons: less automated, more hands on; probably a lower water use efficiency; I imagine that many more plants could be watered then completely fertilized, so supplemental fertilizer would be needed by each plant. (Then again, there would be a lot more plants then in a usual aquaponics system.)

Pros: simpler system; more hands on means more attention; probably easier to keep the system balanced; no integral biofilter to cycle up, so seasonal aquaponics in cold climates becomes more doable; easier to add and subtract may kinds of plants without things getting difficult or the system getting imbalanced.

Any cons or pros I am missing? Is anybody doing this sort of thing?

Some of the very early aquaponics experiments were along these lines, not taking the water out necessarily, but large green water tanks with plants growing in the middle.. Need a suitable fish species and stocking level to suit which will be less than some other system designs.

Have a google on auto-pot designs.

It might be similar to what you're thinking of.

I don't quite understand why the power use for a pump is an issue. Worst case wouldn't setting up solar be acceptable?
Granted not cheap but I'm sure the cost would be offset by the fish and vegies produce....??

The main thing is keeping the fish over the Winter. If you can separate this into a location that's easy to keep warm yet re-attach in the Spring, the rest shouldn't be that tough. If you can't then you need an extremely fast growing species or maybe just grow bait fish

A couple of possibilities for your transfers

1. Use a solar setup hooked to an inexpensive DC pump on a timer - no battery backup (This is something I've been thinking of trying but haven't gotten around to it). The volume pumped might vary but it would take some of the manual labor out of your system. The pump would feed from something like a rain barrel which would feed the fish tank and that would overflow into the wicking beds (and they would overflow as needed). You might be able to use this for extra aeration if needed.

2. Use float valves in the wicking bed area to deliver the water from the fish tank (like a rain gutter garden). No overflow out of the wicking beds this way (except because of rain or problems with level) Water change outs from the fish tank would vary by season with lots in the summer and none or almost none in Winter. In the event of rain, any excess in the Fish Tank would flow out of the FT through an overflow. Probably make a great seasonal garden. (This method is similar to Colum's autopot mention but uses mini float valves - he beat me to the post )

the labour.... needing to do something everyday.


many SE Asia systems and pond type systems do something like this. Although the focus is more on growing the veg within the pond and around the fringes. The nitrification is basically done within the pond (as happens in nature) with the plants removing the nitrates. The addition of floating rafts would be viable (bamboo rafts used already in cases) but you need the basic pond ecosystem in place.

another example is rice paddy aquculture where small cells are used - common in many hill areas and have seen them in China.

Basically scale is your main issue - a small system is highly sensitive and can turn very quickly due to the lack of buffering. Stocking rates, species, dissolved oxygen (DO) and algal blooms are also factors.
(aside from seasonal impacts)

Hello Everyone,

Thanks for your inputs.

Colum, I will look up auto pot designs.

Cunningstunter,

It is not just the power use, though that is part of it. I'm trying to build a system that is easily and cheaply replicated in inner city back yards. Separating the fish tank and plants eliminates much of the power use, the pump, filtration, the biofilter (it is replaced by the soil in the plant pots) the plumbing to connect the two, and thus much of the expense and many of the failure points in a system. It also simplified management; there not longer has to be a compromise between fish and plants. Since the plants will only get part of their needs from the fish, things should be easier to adjust. Some plants may adapt better to this system. Growing media does not have to be fish compatible, and can thus be cheaper. Finally, the fish could live in a warm and sheltered garage or basement, and the plants can be outside in the sun. Theoretically, the tank could be run all winter without any plants growing that way; fish water would be poured into a container of biochar or sawdust which would be used on the plants in the spring, salvaging the nutrients.

Of course, in exchange for this, there is more manual labor.

Scotty; I will look into something like that. Eliminating batteries, etc. makes solar power a lot cheaper.

The float valves might work even better, if the tank and beds were in the same area.

Darren; Wouldn't the water changes make the system easier to balance?

For examples of mini float systems you might want to look at self watering rain gutter gardens on Youtube.

I can't help thinking (oh not again), that there is something wrong witty this picture.
Separating Fish and Plants physically, or mechanically???

First, I am rocking the AP-Boat, by splitting the two completely, but irrespective, I still need pretty much the same power to maintain bio-filtration and fish hygiene etc... ie.. I assume that fish don't like swimming in their own muck, waiting for a.water change..

Yes, I am pushing the.envelope, with very high stock densities, (100 SP in 2000L of water, and virtually no plants), but whilst it has only been fully running for just over a month with the latest hair-brain idea, it IS RUNNING... and the fish are thriving...

It is all based on removing most all solids, but this does increase the labour. A bit.. and filters need to be replaced..

Solids are collected and moved to a mineralisation tank, and that liquid used on gardens..

Ammonia and Nitrites (naturally) do a continual dance, but the nitrates are remaining at zero.
The principle nitrates control, is Biocenosis, or my version of it... just big bags of Zeolite in a sacrificial Flood-and-Drain closed loop media bed..

The firm criticism has been that the Zeolite would saturate and then the whole system would collapse..
So far, so good..
I "believe " that what is happening is that the fine grain zeolite, only partially drains (unlike the clay balls), leaving the core of the bag "slightly anaerobic" and thus it de-nitrifies the nitrates, and then more nitrates moves in to 'fill the void'

I know that some don't trust 'thought' over 'science', but sometimes you have to try things different..

The point is that it DOES seem to be working and thus I could have my fish ANYWHERE ....
I can process the poo, where I want..
And grow plants how they evolved to grow and where they grow best (even hydroponically)

SO.... back to your quote above.. you have described what I am doing, but you have not really said how you would do it..
Eg..I seriously think that the concept of removing water, to remove the nitrogen, would require just sooooo much removal, and then you could not use all that water, thus you would be tipping it, and that would be wasteful of both the water and the nutrients .. and you still need the pumping for the filtration etc..

IMHO



PS.. wherever I have water entering , I use pads of polyester insulation .. as they clog, the water flows OVER the top, and when I see that, the pad is removed and a new one placed there... real easy and fail proof as the worst case is that the filter clogs and water is not filtered

Hello BuiDui,

If I understood you correctly, your point is that removing enough water to keep the tank clean would be far too much water waste?

I'm not sure if this is the case. How much do you think I would have to replace a day, with a stocking density of a pound per ten gallons?

I found a site suggesting three percent per day. So, let's say I have a nine hundred gallon tank, which is large enough to provide a quarter of a person's protein for the year. And let's say I will do a five percent exchange every day. That comes to forty-five gallons a day. Now, a large tomato plant on a hot summer day in the dry climate of Colorado can easily use a gallon a day. Maybe forty-five tomatoes are too may. But I haven't even started watering my squash, melons, broccoli, peach and apple trees, etc.

Or do you think I would need to use more then a five percent exchange?

The zeolite looks interesting. Do you intend to ever change them?

My system has been running as you say for 4 years
The fish look after themselves Fish with a swirl filter to a bio filter when you clean the bio filter or when you need water for the plants use fish water and bio filter muck
As do the plants and the plants running in wicking beds and the waste from them goes to there own sump to be used again also you can add extra nutrients at will
Beauty is if the fish are sick salt them and it doesn't harm the plants
If the plants need spraying you can it doesn't harm the fish
Go to my site I think page 144 for a better description
Just cleaning up- an area for 4 or 6 more wicking beds
Or as was pointed out by one of our esteemed members you cant call them wicking beds
So we will call them window boxes

It's not really that high - I had 220 trout in ~900l of water ( ~ 5X your stocking density) for 7 weeks in my small system (until the big system was ready), with 9 GBs and no extra filtration, with no problems and no fish losses.

GF - As long as you can remove all the fish waste with your water changes, and have enough dissolved Oxygen, dont go too high with stocking density, and the fish dont eat your plant roots, I think it has a fair chance of working.

No BuiDoi, not rocking the AP boat, if I understand correctly you are doing RAS and hydro.

How much water do you use in a week?

Another advantage of simply replacing water; easier to keep the tank warm on cool days without a lot of cycling through grow beds.

and that was my contention, but someone responded that this forum was about Aqua-Ponics..

NO REAL IDEA..

In the AP system - I have a float valve fed from a rain-water tank.. So I would have to mark the tank to work out consumption.. I am guessing possibly 100L a week..

In the AC system, again I could be actually adding about 100L a week..

and both will be from evaporation.. The AC system, only uses about 4L of water to remove solids - not that is pretty efficient..


- if it sits in water, it's probably a wicking bed and it does not know it..

I am building Blue-Barrel Wicking Air-Pruning beds, but whatever I might call them, they will always be wicking beds..
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