Backyard Aquaponics
A place to discuss aquaponics

Interesting topic.

Of course if we can get by with very low flowrates, we could start thinking about things like simple airlifts and maybe a wind-powered pump..

If you go for a constant flow type system with maybe some sprinkler bars over the growbed, a very low flowrate could work.. The problem is going to be that one week in summer where there is no wind and you are hitting 40degrees C outside.. Then the whole windpower idea falls apart.

There is a type of beauty in the idea of a system that is totally freestanding and independent of outside power.
I think the ultimate in low power would be an aerator powered from a solar panel, and relying on an airlift to get water into the growbed. This could be done using a really small solar panel, with the right electronics.

Shucks. I think I am going to try this!

Another crazy idea comes from watching the fish go absolutely berserk at times.
How can we harness the energy of the fish itself to move the water from A to B?

electric eel?

or

attach magnets and have them swim around a copper coil?

Attach magnets!!! Great idea!!

Or....eat the fish, use the energy they give you and bucket the water by hand

Was meaning underwater plants. They add o2 to the water and take out co2.

On the pumpless side, if you lived near the sea I wonder if the tide could be used to move water around(not mixing with sea water)

absolutely you could, probably have a bouy that uses the rise and fall of tides/ waves to move a pump. but i the expense to make that happen would be far more than a pump and solar power/betteries

I remember a couple guys on the tv built a tidel generator. It consisted of a long large diameter piece of pvc mounted virtical to a peir. As the waves pushed water up the tube, it spun a small generator via air excaping the top and then continued to spin it as the water fell and sucked air back through it....I forget what they powered. It may have just been a light bulb.

Anyone seen it? I believe it is a series with a couple british guys that solve various energy problems in a "green" way....or was it mythbusters?

As freo pointed out though, the cost would probably be more then other methods...unless maybe the system itself was on a pier....and then I think you would have a whole shload of other problems.

Remembered this one from South Australia.
Heard they are up to a MK3 version but had some issues with mooring ropes breaking.

Thanks for posting that, Privatteer!

You could make a situation where you have a fishtank of 100 litres, but only put 50 litres of water in it. Then have a sump connected via a hose that hold 50 litres that you can lift up and hang on a hook so that it flows into the grow bed. then have a slow leak so it trickles back into your fishtank, which then flows back into your sump. do it in the morning when you wake up, then again just before your leave the house for the day, then 3 more times at night. and it will work pretty well, at about say 1/4 stocking density that you might expect to get if you had a 20$ pump.

I ran my system for a day with a bucket the first time we had a day long blackout. I just bucketed into the gb until the siphon tripped. took about 3 or 4 minutes per hour. That was about half the water throughput that I was
getting from the pump. All water tests show everything was fine at the end of the day.

Airlifts, yes, and the power of children....they seem to have so much energy !

lol

jeff c

saw a prototype on new invetors energy special a few weeks back...

well i saw pictures and a model the actual proto got blown away in the qld floods cyclones etc earlier on

i thought it was an amazing idea using the sea to create wind then moving a turbine, would last many times longer than anything acutaly imersed in sea water

Cheers
pete

Been thinking about this problem for a bit and my tentative solution would be a single shallow long trough like tank. There would be a permeable divider like a screen down the length of the tank. One side would house the fish and the other side the growbed. Nitrogenous wastes could passively diffuse from the fish side to the plant side. The length of the longer narrow FT/GB would hopefully allow enough fluid exchange as well oxygen exchange to keep the system running. Looks good on paper but dunno how it would execute in real life. Thoughts?

Biggest problem would be lack of circulation causing lack of dissolved oxygen in the plant side and perhaps anaerobic conditions. This might not become a problem if there is very minimal fish but as soon as you start feeding any fish in there, the problems will probably show up.

If you're going with small amounts of inedible fish then why not circumvent the fish. I mean it's just a waste of energy (unless moving water is for someones amusement). Why don't you get some worm castings and steep them in a nutrient reservoir(or some pee-ponics) for passive hydroponics. Now, I know this is a aquaponics forum, but using fish in this situation is wasteful and expensive. (patting on the back emotocon)
Personally I've never made my own nutrients but, there is some good stuff online about this on hydro' sites and this group on Sylvia's forum (http://aquaponicscommunity.com/group/fish-less-systems).