Hi
The excess nitrogen thingy from
http://www.tmc-ltd.co.uk/filtration/essenti=
al_equip/aeration_equip.asp : -
Technical Facts
A medium sized air bubble of 3mm will rise at a rate of 1 ft/sec and hence,=
a bubble released from a depth of 3 ft will have a contact time of 3 secon=
ds. Air injected at depths greater than 4 ft can lead to excess nitrogen di=
ssolving in the water. This can result in what is commonly known as 'air bu=
bble disease'.
Smaller bubbles can be created using air stones with smaller pore sizes. Ho=
wever, with this reduction in pore size comes an increase in the pressure r=
equired to produce the bubbles. Smaller pore sizes also have a greater tend=
ency to become blocked. This can occur through dust in the air inflow, the =
formation of calcium carbonate (especially in hard and saltwater) and throu=
gh a build-up of bacterial slime on the external surface.
An edited response to my query to the site says: -
"Air bubble disease is a similar to the physiological effects of nitrogen n=
arcosis which occurs in divers. In a pond or aquarium it occurs as a resu=
lt of over-aeration and causes supersaturation. Supersaturated water may c=
ause embolisms in the organisms. This can be observed as tiny bubbles parti=
cularly in the eyes and fins of fish and under the skin.
If you are worried that aeration may cause supersaturation, consider using =
a bio trickle tower - this will produce a regassing effect to re-oxygenate =
water, but also benefits by de-gassing saturated gasses such as nitrogen.
I hope this has been of some help to you. Unfortunately I do not have any =
additional information to forward you. However, I will pass your enquiry o=
n to one of my colleagues and hopefully he will be able to provide you with=
more information."
I haven't been able to find more on the subject.
Be well
Stuart Baxter
bits 'n bobs
----- Original Message -----
From: Robert Norsen
To: compost_tea_at_yahoogroups.com
Sent: Thursday, October 30, 2003 3:29 AM
Subject: Re: [compost_tea] Re: Getting Oxygen into Tea and Preserving Fun=
gi At The Same Time
Thanks, will try. .Find anything significant will report. Bob
chriscreid <reidchris_at_earthlink.net> wrote:
Bob Norsen wrote:
> Chris, I am concerned about your " air injected below 4' may
result in excess nitrogen disolved in the air" there a web site or
other source where I can learn more about the subject? Bob .
>
> Bob,
Though I'm only the messenger on the nitrogen level question, it
said that air in depths GREATER than 4 feet might result in
increased nitrogen dissolved into the water. First, that will be an
issue for fish, but is it an issue for tea? The link was sent in
DCHALL's post - check it out, maybe you can backtrack it and find
out what the aquarium folks know about this.
Chris
Received on Thu Oct 30 2003 - 19:49:57 EST