Aquaponics Digest - Fri 02/25/00
Message 1: Quantification of Tiny Bubbles - DO
from Bill
Message 2: Re: Damn!!
from "Hairo Jairo"
Message 3: Re: Damn!!
from "Sam Levy"
Message 4: Re: tilapia in Canada
from Joy Pye-MacSwain
Message 5: Re: Quantification of Tiny Bubbles - DO
from "Lloyd R. Prentice"
Message 6: Fwd. - RESOURCE, new Web Listing
from S & S Aqua Farm
Message 7: Quantification of tiny bubbles - DO
from Peggy & Emmett
Message 8: Re: tilapia in Canada
from Mike Price
Message 9: Re: Quantification of Tiny Bubbles - DO
from "Sam Levy"
Message 10: Re: Quantification of tiny bubbles - DO
from "Sam Levy"
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| Message 1 |
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Subject: Quantification of Tiny Bubbles - DO
From: Bill
Date: 25 Feb 00 00:59:44 PST
>>Bill,
>> DO is driven up in a variety of ways. there used to be an arguement
about > smaller bubbles being superior "due to increased surface area of
smaller> bubbles." Turned out to be impact of a bubble's bursting was the=
greatest > factor.
>Is this definate? How much of a factor? This seems relevant for raft
systems in particular - possibly good news if the raft shape is altered
to take account of this?
>Barry
-------------
*How much of a factor is hard to quantify, as bubble size, etc play a par=
t. =
Perhaps you recall old port flow theories that went to two schools. Roug=
h
intake ports atomise the gas/air. Or, smooth bore flows more. #2 won, w=
hen
tests finally done. How much? It depends on....etc.
Old school was, water flow to surface... surface to air diffusion was the=
key.
So a pump and circulation was the answer, smooth laminar flow was fine. =
Bubbles added surface area and circulated water too... double benefit and=
cheaper pumps. Some buddy figures out smaller bubbles, greater surface a=
rea. =
But it didn't seem to help in a predicted proportion is my guess. It was=
not
stated.
Turned out, water impacting water, helped oxygen, etc, cross the threshho=
ld of
energy required to do bond breaking and reforming.
Tiny bubbles have greater overall impact due to size creating greater coh=
esion
of bubbles' water. And more of them helped. Enuf to more than compensat=
e for
reduce flow due to backpressure caused by smaller orifice diffussers.
So a waterfall system also fills the bill, or any impact system. Rotatin=
g
discs with holes, squirters, tho they are energy intensive.
But a decent airstone seems the way for smaller systems. Sorry no number=
s. =
To many variables. Was very marked though.
Bill
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Subject: Re: Damn!!
From: "Hairo Jairo"
Date: Fri, 25 Feb 2000 20:25:52 +1000
Hey man,
I am really sorry too !!!!!
What's this, "dumping over the internet ?"
Any way, TKYU very much for your postings.
I'm learning a lot.
I haven't even started yet. I am still stuck in composting.
Do fish eat compost ?
----- Original Message -----
From: Steve
To:
Sent: Thursday, February 24, 2000 5:46 PM
Subject: Damn!!
> This is probably going to be the most unprofessional post that I will ever
> do.
>
> I'm just really "bummed"!
>
> I just finished cleaning my tanks and for no reason whatsoever, that I
know
> of, everyone of my babies DIED! (Almost 400 of them!!)
>
> I mean, this is not the first time that I have cleaned tanks. I started
> noticeing a few floaters and then a whole bunch of floaters and then
> everyone was acting erratically in both 10-gal's...and then shortly after
> that...they were all DEAD! I'm suppose to know what I am doing with this,
> but this baffles me. Yes, the temp was o.k.
>
> Sorry, I'm just "venting". I'm really sad about this. I go to a lot of
> trouble with these guys!!!
>
> I have to vent to someone and no one else would understand.
>
> Sorry, for this!! but....DAMN!!
>
> Steve
>
>
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| Message 3 |
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Subject: Re: Damn!!
From: "Sam Levy"
Date: Fri, 25 Feb 2000 04:23:06 PST
>"supersaturated water"
> >
>supersaturated water- what's that? Too much oxygen?
in this context it means that the water in oversaturated (more than 100%)
with atmospheric gasses--although the concern is generally over excess
nitrogen. the physics are similar to "bends"--
sam
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Subject: Re: tilapia in Canada
From: Joy Pye-MacSwain
Date: Fri, 25 Feb 2000 09:02:35 -0400
Morning Chris.....
Sorry to have been slow to get back to you but it is the end of Feb. and that means
quarterly
report time ... ugh!!!
> Could you please introduce yourself to the list with a short description of your
> system. Are the fish and plants in a greenhouse or do you do them separately? I
OK.... we built a system based on the S&S model Victoria Day weekend (May '99).
That was an amazing experience.... just like an old fashioned barn raising with over
30
men and women starting at 7:00 Am and going all day. At the end of day, one
completed
greenhouse, completely enclosed, well hooked up, power on. The rest, tanks, growing
beds
and plumbing we finished over the next month. The greenhouse is 3000 square foot
with six 800 L tanks, each with six 8' x 4' growing beds apiece. So water from each
fish
tank is pumped to the associated growing beds of pea gravel to provide nutrients for
the plants,
water from the beds drains into the node sump ( each grouping of tank and beds are
separate
from any other) and then water is returned to the node fish tank. We also have two
500 L
tanks for our brood stock (originally brought in from Thailand last fall), and we
will be breeding
our own stock as soon as these guys get big enough for us to sex and then
separate.....
hopefully no little ones before that...:) :) :). The entire greenhouse is operated
via a
computer monitoring in tank heaters, air pumps, furnace and fans. One half of our
facility
is devoted to experimental work such as fish and plant density studies and the other
half is
a commercial operation...... mind you it is me still doing both but.......:) :) :)
Our tilapia, originally brought from Northern Tilapia, are doing very well and I
expect to put
our first animals to market within the month. We have grown tomatoes.. part of the
experimental
system and currently are working with bell peppers and English cucumbers. On the
commercial side we grow primarily basil (our top seller), arugula, parsley, cucumbers
and peppers with some tomatoes for a select number of clients. Most of our product
is going
to Superstore, but we also sell directly to a couple of restaurants. The current
experimental work
is centered on densities of plants and fish... how great can we take each and still
get good growth
with saleable product; we are also looking at a variety of growing structures fondly
referred to
as the gizmos with utilize the tank water but do not use pea gravel... so a sort of
NFT system using
fish water with plants supported in PVC pipe and plants supported in cups containing
hydraton
(I think I have mis-spelt this) balls; floating or raft systems are also being looked
at.... I spend
a lot of time doing water qualities from individual pipes, measuring plant heights
etc.....:) :) :)
>
> have had great luck with red, yellow and orange peppers, but my basil doesn't do
My first peppers should be ready for market within the month...can't wait..:) :) :)
>
> too well during the months of nov, dec, jan. The greenhouse has so much humidity
> and dripping from the roof during those months that the basil ends up with cold
> damage.
We experienced similar humidity problems but found that by adjusting our internal
fans so that
they pointed towards the roof in stead of along the walkways that we were able to
keep better
air circulation going and reduce the amount of water accumulating on the roof. The
other thing
that I regularly did was manually (the computer thought I shouldn't do this because
internal temps
didn't indicate that I should be venting) vent the greenhouse air for 5 minutes at
least twice each day.
That kept fresh dry air coming into the greenhouse and moving some of that humidity
out. This
wasn't a total success but I did see significant reductions in my losses (relatively
speaking) compared
to the losses of Nov. I know this doesn't help you right now but it is a thought for
next year.
Where are you located Chris??
Joy... who is celebrating a full week of sunshine and very happy plants!
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| Message 5 |
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Subject: Re: Quantification of Tiny Bubbles - DO
From: "Lloyd R. Prentice"
Date: Fri, 25 Feb 2000 11:27:39 -0500
Hello,
Bill wrote:
> So a waterfall system also fills the bill, or any impact system. Rotating
> discs with holes, squirters, tho they are energy intensive.
> But a decent airstone seems the way for smaller systems. Sorry no numbers.
> To many variables. Was very marked though.
At risk of posing a foolish question, I've wondered for some time if one could maintain
minimum acceptable DO by enclosing water plants in a cage that floated or rested in the fish
tank?
By selecting plants that the fish like to eat, the fish would consume any shoots that escape
from the cage. I understand that this would consume precious tank space, and perhaps reduce
the nutrients available for revenue-producing crops but, if it worked, I'm wondering if the
insurance value against losing fish might be worth it.
Best wishes,
Lloyd R. Prentice
--
Prentice Associates Incorporated
Creativity, technical excellence and professionalism in print, web and software communications
for the health care and high-tech industries.
See us at: http://paisite.com
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Subject: Fwd. - RESOURCE, new Web Listing
From: S & S Aqua Farm
Date: Fri, 25 Feb 2000 11:31:19 -0600
Here's a link to the just published Aquaponics page at ATTRA. What a
wonderful resource they are!!
Paula
----------------------------------------
>Date: Fri, 25 Feb 2000 10:35:39 -0600
>From: Ruth Raborn
>To: snsaquasys@townsqr.com
>Subject: Web Listing
>
>Just wanted you to know that we (ATTRA) have added a new publication
>entitled 'Aquaponics - Integration of Hydroponics with Aquaculture' to
>our web site. You may find this pub at:
>
>http://www.attra.org/attra-pub/aquaponic.html
>
>Thanks for your input to Sustainable Agriculture!
>--
>Ruth Raborn
>National Center for Appropriate Technology (NCAT)
>Appropriate Technology Transfer for Rural Areas (ATTRA)
>Fayetteville AR
>(501)442-9824
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| Message 7 |
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Subject: Quantification of tiny bubbles - DO
From: Peggy & Emmett
Date: Fri, 25 Feb 2000 15:02:29 -0500
I'd like to jump in here with some real time info.
Inasmuch as my systems are new I'm experimenting with minor variations to
the S & S system.
One node sump return is piped into a cross of one inch diamter pipe. Each
arm of the cross contains 28 quarter inch holes. This makes for 112 holes
through which return water is pumped. The cross quarters the poly tank with
the pipes resting on the ledge. The pipes are turned downward at
approximately a 45 deg angle which causes the tank water to turn in a
clockwise direction. The water is returned differently from each arm due to
some unknown (to me) law of fluid dynamics. It's fun to watch. In building
this return system I imagined that all these streams of water with their
concomitant bubble streams would give me a high DO. At this point let me
say that I'm ordering fish next week. I'm running the system to establish
my bacteria and get the plants established. I have a Hach aquaculture
testing kit. At 1 P.M. today my DO was 9 mg/L.
>From the other node sump the water is returned by a 1 1/4 inch pipe stepped
up to a 3 inch pipe. This pipe is capped. The cap has 37 quarter inch holes
in it. When it goes off it startles people. Water is shot in at a 45
degree angle with enough force that it appears to go at least a foot below
the surface. The bubbles trail out about four feet. This tank too is
swirled in a clockwise direction. At about 1:15 P.M. today the DO was 12 mg/L.
When I came up with the cross return I was certain it would give me a
higher DO. My partner, a veterinarian, and one of his employees, who raises
both fresh water and marine fish for a hobby, concurred. Duh! So much for
genius.
Further, the multiple stream cross system has proved to have three negatives.
1. High evaporative loss. Contributing to an existing high humidity level.
I replace from 2 to 4 inches of water daily depending on the weather.
2. Ever increasing salt levels in the tank. My well water runs about 32
mg/L. But the salt doesn't evaporate. So it slowly builds up.
3. The nuisance of having to fill it up everyday.
Hope this helps the discussion.......Emmett
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Subject: Re: tilapia in Canada
From: Mike Price
Date: Fri, 25 Feb 2000 13:38:44 -0700
Joy Pye-MacSwain
Hi, My name is Mike Price, and I live in El Paso, Texas. It sounds like your operation
is going great!
I was curious where you are located, as I am trying to find an S & S operation that I
could visit.
Thanks,
Mike
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| Message 9 |
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Subject: Re: Quantification of Tiny Bubbles - DO
From: "Sam Levy"
Date: Fri, 25 Feb 2000 18:18:42 PST
>At risk of posing a foolish question, I've wondered for some time if one
>could maintain
>minimum acceptable DO by enclosing water plants in a cage that floated or
>rested in the fish
>tank?
>
>
>Lloyd R. Prentice
>
>
lloyd-
the closest i've ever seen to this is commercial aquaculture is the use of
green (algae) water. briefly, the algae would "steal" nutrients from the
vascular plants, create additional solid wastes, and--like all
plants--become oxygen users at night
sam
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| Message 10 |
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Subject: Re: Quantification of tiny bubbles - DO
From: "Sam Levy"
Date: Fri, 25 Feb 2000 18:31:03 PST
>When I came up with the cross return I was certain it would give me a
>higher DO. My partner, a veterinarian, and one of his employees, who raises
>both fresh water and marine fish for a hobby, concurred.
Emmett
emmet,
you don't mention the water temperature nor do you mention the %saturation
of the water.
replenishing oxygen in the water that requires both contact time & surface
to be effective. you might, of course, swap the return arrangement on the
two systems you mentioned in order to be assured that your result is a
function of the pumping system & not differing o2 demands of the two systems
(bacteria--the ones you're trying to culture require o2 as well).
you mentioned using a chemical test kit of o2 measurements (i assume it's a
winkler or modified winkler titration)--have you compared the cost of
monitoring this way as opposed to a DO meter (& using the titrations once
every 3 - 6 months to double check the instrument's calibration)?
sam
>
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