Aquaponics Digest - Fri 03/10/00
Message 1: unsubscribe
from Jennifer Maynard
Message 2: Re: Any suggestions
from "James Rakocy"
Message 3: System and greenhouse for sale
from Robin Jenkins
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 1 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: unsubscribe
From: Jennifer Maynard
Date: Fri, 10 Mar 2000 02:19:58 -0400
unsubcribe
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 2 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: Any suggestions
From: "James Rakocy"
Date: Fri, 10 Mar 2000 11:26:56 -0400
This is a complex question. Nutrient levels are related to the amount of
feed added to the system, the area devoted to plants, the type of plants and
the water volume of the system. Most systems apply approximately 50-60 g of
feed per square meter of plant growing area per day. Let's say you have a
1,000 gallon rearing tank and will raise 500 lbs of fish with a feed
conversion ration of 1.5. Total feed added to the system would be 750 lbs
in a 180 day growing period for example. Average feed is 4.17 lbs. per day
or 1892 g. Dividing by 50 g/m2/day, you will need about 38 m2 of plant
growing area. It's hard to detect any drop in nutrient levels as water
flows through the hydroponic tanks, but a relatively steady state will
develop. By steady state I mean nutrient levels will fluctuate within an
acceptable range. You should take our 7-day course at the end of June if
you want to learn more about aquaponic systems. Jim R.
----- Original Message -----
From:
To:
Sent: Friday, March 10, 2000 12:42 AM
Subject: Re: Any suggestions
> In a message dated 3/9/00 10:48:43 AM Pacific Standard Time,
jrakocy@uvi.edu
> writes:
>
> >
> > > Could you also advise on fish density and water flow rate
> > > for close looped systems.
> >
> > You should shoot for a final rearing tank density of 0.5 lbs/gallon (60
> > kg/m3) and an water exchange rate in the rearing tank that can vary
from
> > roughly 60 minutes or greater at stocking to nearly 30 minutes at
harvest.
>
> Hi all,
>
> Any idea on the amount of nutrient that could be available at max fish
> capacity and with an exchange rate of 30 to 60 minutes?
>
> Do you expect to have fairly clean water, clean of all nutrients, from the
> return line at these rates?
>
> Thanks, Joel
>
>
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 3 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: System and greenhouse for sale
From: Robin Jenkins
Date: Fri, 10 Mar 2000 19:45:57 -0600
Hi everyone,
My name is Robin Jenkins and I've been on this list for a little over a year
now. You are really a great bunch of people and the list is one of the
friendliest and most cooperative I've encountered on the net. I asked
permission from Paula to make this offer in light of the non-disclosure
agreement we have and she graciously consented.
I started my system last February for several reasons: an interest in
integrated gray water treatment in residential dwellings, an interest in a
small business venture in biointensive agriculture, and I like fish and
plants so it seemed like a natural. Time constraints and new interests make
it so that I can't give aquaponics the kind of attention it demands for the
foreseeable future, so I must shut it down. I hate to just junk all the
components but that is what will eventually happen whether I want to or not.
I know that there are those on this list who could make use of parts of if
not the whole system.
How much? It's negotiable. Let me say that I really don't care to make any
money, just recoup a portion of the investment in terms of the materials
used. The system has worked beautifully for me since I cranked it up. The
design principles follow closely the S & S model, with a few changes. I
have spent well over $6500 on the whole thing and have receipts to prove it.
So would $4750 be fair? Make me an offer. I will come and help you set it
up and get it going for the price of the hotel stay, maybe less if you live
somewhere I would want to vacation. I'll show you how to program the
computer and throw in a nursery tank I made out of a 55 gallon plastic
drum! Now that's a deal! The whole system and greenhouse can be loaded in
a pickup and 16' flatbed trailer.
System:
Fish tank is a 1000 gallon sloped-bottom, blue poly tank. I currently have
300 Pennyfish tilapia of staggered ages stocked. The tank is supported on a
wooden stand that keeps most of the water above the level of the grow beds.
A 3" PVC "manifold" pipe drains the tank. A 3" PVC 24volt motorized drain
valve is controlled by a Programmable Logic Controller (PLC), a small
industrial computer. It opens every two hours and closes when the grow beds
fill up with water. 1" PVC pipe taps off of the manifold for each of the 5
grow beds, with a 1" PVC ball valve to cut of each individual bed and
regulate water flow. 1" PVC irrigation grids help to start plants, then are
removed for the flood and drain phase. There is another 24volt motorized
drain valve on the drain for all of the beds. It controls the flood and
drain cycle and also works off of the PLC. Water drains by gravity into the
grow beds and then into another 800 gallon reservoir tank that is below the
level of the grow beds. This reservoir contains the only pump that is
controlled by a level control in the main fish tank. Everything is fail
safe, so if a motor valve fails, or a pump fails, or the computer fails,
the fish tank is not emptied. I also have a spare for everything, motor
valves, pumps, etc.
The PLC is easy to program and has several more inputs and outputs available
for things such as automatic feeders, alarms, monitors, etc. It is also
expandable. The pump is 1/4 hp and only runs 15% of the time if you keep a
2 hour flood and drain cycle. My cycle is: water circulates over the grow
beds for 7 minutes. This gets the water in the fish tank spinning like a
toilet. After 7 minutes, the drain closes and the beds fill up. They stay
flooded for 30 minutes and then drain. Two hours pass before the cycle
begins again.
Grow beds are 3/4" Marine grade plywood coated on the inside with a food
grade epoxy. There are 4- 48" x 72", and 1-48" x 84". Each has 2x4 base
and cynderblock stands. They are lined now with 6 mil poly-plastic, but I
would go back with 20 mil EPDM pond liner or better.
If you could work it you could also have my gravel and lava rock grow media,
complete with one of my favorite parts of the system- Eisenia Foetida! Red
Wriggler worms! I have an excellent population and they keep things clean!
Greenhouse:
The greenhouse is wood framed, 14' x 20' lean-to. 12' at the highest down
to 7' at the front. It is plenty roomy, and big enough to keep from
overheating. It has 1 wind turbine as a vent, but I recommend installing 2
more, they're cheap. The glazing is corrugated Polycarbonate, lifetime
guaranteed. Glazed inside and out on the roof and front. The roof and
front are glazed with the Poly Carb. and the sides are done with cheap 6 mil
poly plastic. Wood strips screw on the poly and the whole outside can be
replaced in an afternoon by one person. The roof is 2x6 joists on 48"
centers, and the walls are 2x4 studs on 24" centers. There is a good storm
screen door that came from my mother's house. The whole thing is screwed
together and can be disassembled and moved.
I think if you live in the southern latitudes, you could go without the
glazing on the inside and use it to glaze the sides. I heated the water
with a homemade heater using water heater elements and styrofoam and the
warm water kept the greenhouse toasty all winter long here in Lubbock, TX.
Whether or not you're interested in buying, all of you are welcome to come
and take a look at my system any time. It is still up and running with
tomatoes, peppers, basil, aloe vera, swiss chard, and most amazing -
Ficus Trees! You can also contact me off list if you want at
hotrob@swbell.net . Thanks for reading and all the information you've
provided over the last few months. I especially enjoy you Ted (TGTX). Like
to meet you some day. Stop in if you're in my neck of the woods, 'course
there are no woods here, just wind and dust.
Robin Jenkins and /. .\
(.)
.
|
