Backyard Aquaponics
A place to discuss aquaponics

I have been studying the system designed by the University of the Virgin Islands and would like to try a similar style setup.
For any who have not seen it the link is:

http://rps.uvi.edu/AES/Aquaculture/aquaponics.html

They have it designed so that the sump pump is pumping continuously and added water forces water through a center drain by hydrostatic pressure and flows to the settling tank and on to the rest of the system. I have not seen another system with this concept... tipically we would bury the fish tank in order to use just one pump. I would appreciate any comments/thoughts on how this would be effective or possibly varried so all the conections are not under the ground.
Also with the hydroponic tanks(grow beds)...they are made with concrete or concrete block walls and lined with a pond liner. My first thought was couldnt it be dug down into the ground so you would not need to construct walls? And then another thought... I read somewhere of people using ferro cement to make tanks/growbeds. If I was to dig out an area for this hydroponic tank and use ferro cement to line it instead of a pond liner would that work? I believe it would be much cheaper....
Your thoughts and inputs would be appreciated.
Oh, and of course I would need to put this system in a greenhouse to be able to regulate tempurature, too bad I dont live it the tropics!! *sigh

Ral

Welcome Ral,
There are time tested systems and then there are all us backyard Aper's who have developed our own set of rules. Use what you can get ahold of and grow fish and veggies.
If you haven't yet have a look at the system threads and see what others have done.
To answer your questions, you can do Ap anywhere with anything more or less as long as you keep the fish alive.
Now post some pictures to get all the folks in the cold spots drooling.
NC is the tropics, what you talking about?

Digging out and lining grow beds- yes!

There was a forum member here who had a simple setup like that awhile ago, and to me it makes a lot of sense if the usual grow beds are too expensive.

Ferro cement tanks - yes!

DTHawk here is experimenting with ferrocement grow beds. He has built several systems using concrete for tanks and beds.

My system (in the basement) and Earthbound's (Joel the Founder) CHIFT PIST (constant-height-in-fish-tank pump-in-sump-tank) system use the kind of drain you mention. I of course cannot bury my tank, so I just used a straight pipe down to the bottom of the fish tub, up to a tee at water level, and horizontally out to drain into the sump, which is only slightly lower than the fish tub. Water coming in to the fish tub from the gravel beds pushes the water out the drain due to the pressure.

VeggieBoy has a CHIFT PIST system like Joel's as well.

Chift Pist link:
http://backyardaquaponics.com/forum/vie ... 8997#58997

DD I'm building something similar and was wondering if there would be enough velocity to pull the solids off the bottom of the tank. Do you have any problems with that?

I have been to the local hardware store and the only cement they have is quikcrete varieties and no one can tell me if they are non-toxic or suitable to use with fish. Where does one find this ferro cement? Then if I was to make a growbed 12 feet by 97 feet how thick would the cement need to be with all that water pressure?
I was also hoping to be able to grow lettuce year round in a greenhouse where I can monitor the temperature. However after visiting a local nursury I was advised that I might as well forget trying to grow lettuce in the summer months... apparently (by what I was told) being in the greenhouse will only lower temps by about 10 deg. and when lettuce gets too warm it goes bitter.... Is there any advice on this? I would really like to think I can grow lettuce all year, and have the same quality even in the summer.

Ral

They're probably not factoring in the constant supply of water to the lettuce..... not the case in soil operations, and lettuce is basically all water...

Run it dry and hot and the lettuce stresses and goes bitter.... usually bolts as well

It is amazing how fast info can be accumulated here!! Thanks rup for such a quick response. I also have the issue of keeping the water warm for tilapia. Would that change anything?

I don't think so.... there are quite a few members raising Talapia so I'll let them comment with more authority...

My take would be utilising "flood and drain"... the roots wouldn't be exposed to the warm water long enough to be a problem....

Running "continuous flow" like a UVI system.... well it obviously works in a very warm location and I'd have to expect that the ambient water temperature is warm.... perhaps running in long channels has the effect (evaporative) of cooling the water somewhat....

Conversely, a flood and drain system like most of us have utilises growbeds with media of some sort.... exposure to sunlight/temperature results in a transfer of ambient heat to the system water.... again seemingly without any significant deleterious effect on the plants... in fact I believe they like it

Just to add to this..... this is exactly what happens in a hydroponic operation unless steps are taken to monitor and maintain temperature within certain limits.....

Also has a secondary effect in hydroponics of precipitating out salts, clogging drippers, affecting pH/EC and locking out nutrients

Many large commercial operations run the nutrient return through buried pipes to a shed enclosed buried tank and cooler setup.

I don't have good enough light to grow lettuce (It gets spindly), so I can't tell you if it's a problem in combination with tilapia-bath-water. Most plants like a little root warmth, though. Plant different things and see what does best for your conditions. My best two veggie plants have been basil and eggplant. atm though, I am planted mostly in tropical ornamentals.

Have a look to this video, sorry it is in french but with the images you could still understand the basics, this man produces trouts and lettuce on floating rafts
Might give you an answer to your question
http://www.radio-canada.ca/actualite/v2 ... 605.shtml#
just scroll down and click to the "aquaponie" video I am sorry I've not found the way to do a direct link
amacafish

Grow leaf lettuce. I have grown spinach in the summer (up to 90°F), but you got pick all those leaves quick. Makes a lot of baby spinach. If it starts to bolt, pull it out.

If you are willing/able to dig, this is by far the least expensive. You are not talking about a much depth, and it would assist somewhat in controling the temp. Like Janet mentioned, basil does real well in the floating rafts, there are a number of commercial out fits doing this.

I am growing loose leaf lettuce in the AP system (mid summer plus hotter in the green house), it has a slightly bitter taste but not too bad.

The lettuce are taking about 6 weeks to grow from seedlings and I am still harvesting at least six weeks later before they begin to bolt.

I get the seedlings from the local markets, so they would be a suitable variety for the local conditions...at 10c each, I get a dozen every 2 months...feeds the fish too

I know its been a while since I first started this post, but I have been putting a lot of thought lateley into the design and it would save a lot of space if I use vertical towers. So to begin with... how does lettuce grow in a tower? I dont recall if anyone has tried it. Then based on the spacing used by the system in the Virgin Islands, I figure that the spacing for romaine lettuce would be 10 inches and for leaf lettuce 6 inches. If I use a 6 inch pvc pipe 6 foot high I think I should be able to put the lettuce on 3 sides of the pipe.... leaving one side to anchor it to some type of support. Then with 2 feet walking space between rows, based on my math I could fit enough pvc towers in an area 30 foot by 12 foot to grow the same quantity of lettuce as grown in the 12 foot by 96 foot grow beds used at UVI. I am sure there are many things I have not taken into consideration... but I am wondering how this sounds. Would the spacing be sufficient so all the plants get enough light? I realize that if filled with gravel these towers would be extremely heavy, mabe use coco peat? Then I am not sure if it would be best to have continuous flow or drain? And mabe I could have them drain into other grow beds on the ground... So many thoughts. This hasnt been as organized as I would have hoped, but if this would work it would save so much space... and that makes me so excited I am sure I am overlooking things...
So I am hoping to get some input on my thoughts