Re: [compost_tea] D O Meter

From: Ted Peterson <ted.peterson_at_tcsn.net>
Date: Tue, 2 Mar 2004 12:51:24 -0800

----- Original Message -----
From: Mark Garrett
To: compost_tea_at_yahoogroups.com
Sent: Tuesday, March 02, 2004 12:13 PM
Subject: Re: [compost_tea] D O Meter


What is a D O Meter and what is it use for?
Thanks,

A DO meter is a Dissolved Oxygen meter. It shows the amount of O2 dissolve=
d in your water. Standing water contains a certain amount of dissolved O2.=
 If you start with a tank of water and the DO indicates 7 say it will lower=
 when you add compost and air and start brewing. This is because the micro=
bes you are wrangling (Feeding and giving O2 to.) in the tea are using the =
dissolved 02. It might lower to 4 - 5. Now, if you unplug your air, you w=
ill see the DO drop to zero in most cases. This is because the bacteria/fu=
ngi are using up all the O2 during the process of eating. Reconnect air an=
d the DO will rise.

So, you use the DO meter to determine if something is using the O2 in your =
water. If you are providing an environment for bacteria to grow and fungi =
to extract from compost, you can make a safe assumption that this growth wi=
ll be reflected in O2 use.

It is a valuable tool to determine that you are getting some kind of biolog=
ical activity in your tea. However, while it tells you that your bacteria =
are growing, it doesn't tell you the diversity of that bacteria. So it is =
a crude measure but one that works to show something is happening.

Now, if you are using a reputable brewer with some recipes, you shouldn't n=
eed a DO meter if you are just brewing for your lawn and garden. If howeve=
r, you want to experiment with foods and different strategies for aeration,=
 a DO meter is a very handy and necessary tool.

Ted Peterson
Earth-Wise/Spirit of the Earth





Received on Wed Mar 03 2004 - 02:00:08 EST

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