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Re: NO3 and PO4 in Takashi Amano Aquaria
- To: Aquatic Plants Digest <Aquatic-Plants at actwin_com>
- Subject: Re: NO3 and PO4 in Takashi Amano Aquaria
- From: Chuck H <grendel at usit_net>
- Date: Mon, 02 Jun 2003 03:53:43 -0400
John Fitch wrote:
There are two further measurements given [in Takashi Amano's TAG article],
which I hope someone will
explain. They are TH of 20-40 mg/l and COD of 4-6 mg/l. Thanks.
I suspect TH = total hardness. COD = chemical oxygen demand. It's defined
as the amount of O2 required to oxidize both inert and bio-available
organic compounds into CO2 and water. The decomposition process uses up
dissolved oxygen (DO) that fish and other animals need, so I assume that
Amano-san uses COD as a measure of water quality (lower = cleaner), but he
may have other motives.