Re: [compost_tea] Re: Re: measuring aeration

From: Robert Norsen <bnbrew_at_yahoo.com>
Date: Mon, 13 Oct 2003 09:56:29 -0700 (PDT)

!0 PSI Kirk? maybe you can but you would be super man. 1 psi is about it for a human blowing HARD. Testing I did on Bitti air system was with the aerator restrictions in place. Just over 1 cfm.
 
Why don't water pumped systems report the air they generate? I think they would have a hard time measuring the air injected by the water action.. Bob
 
 

Kirk Leonard <kirk_at_oregonatural.com> wrote:
Well, Sunday, good sunny wintery day here (rains have come...YES!), and good
to understand more clearly barometric effects and use of oxygen probes.
Still feels like being wrong is better than not asking ... though I have
seen baro moves as much as 2mb in a day, and we don't have hurricanes here
in Pacific NW, save 100-year storm hurricane-like events...probably wouldn't
be using tea that day...:)

On Bitti air volumes, I find Doc E's description a bit of a conundrum. I
bought a Bitti pump from Bob (special exchange, don't know he sells them
standalone, do believe they are good pumps), and its free air volume was
right at 1cfm, maybe a fraction less. It roils well in a 15 gallon system,
pushing 14 inches of water (about .5 psi, so not much back pressure). My
aerator passes a good bit more air than Bob's, mayhaps there's a constraint
there? If there's not enough air in a Bitti, how is Paul S getting his good
results? And the Bitti seems sized well per Paul W's air volume suggestion.
I really want to believe there's enough air there.

Would that all tea machine makers were upfront and clear about air volumes.
Part of my flustration here is that doesn't seem to be the case. Thank you
Bob and Carole for some info, others who are making machines and testing
need to speak up, imo. What's the free air or open flow cfm rating of a
pump (or blower), and what's cfm under load, with aerators at design depth?
Two questions I'd ask, anyway, latter seem most important.

All good air pumps and makers have air volume tables of water depth/psi
load/volume specs (except aquarium pumps, it seems - thanks Tom J for Hagen
info, tells some -), why not compost tea machine makers? Horsepower is not
a good indicator, by the way ... air is real different from heavy objects
and air into water doesn't need a lot of Hp or pressure capacity. Unless
you're making tea in a deep well, tiny horses and 4-5 psi air pump capacity
is enough, I think. You don't need horsepowers of electricity to make
compost tea.

A human can produce a lot of air pressure, hmm? If you hold your breath and
push, I bet you can do at least 10+ psi... a burst in several cfm vicinity.
Anybody got a bead on that? As Jeff originally asked, "I wonder [how] much
O2 is just enough?" I'm wondering what might be a useful maximum, too.

Kirk L








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Received on Mon Oct 13 2003 - 15:32:09 EDT

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