re: assorted things

---------- Forwarded message ----------
From: psears at emr1_NRCan.gc.ca (Paul Sears)
Message-Id: <9701300237.AA15560@emr1.emr.ca>
Subject: Re: Aquatic Plants Digest V2 #484
To: Aquatic-Plants at ActWin_com
Date: Wed, 29 Jan 1997 21:37:56 -0500 (EST)

> From: RevWCw at aol_com
> Subject: Nitrate Test Kits / Fertilizers
> A thought conceived last night while testing the tank:  An "undetectible"
> result in a nitrate test should always be verified by adding a drop or two of
> nitrate containing solution (such as PMDD) to the test vial before you dump
> it just to be sure that the reagents were active.  I've noted several false
> "undetectible" results with a recently purchased Wardley kit.
	The nitrate tests I have seen use a two-part reaction in which
the nitrate in the original sample is first reduced and then measured
in another form.  Putting nitrate into the mixture at the end of the
test - after the second step - may well not work.

Paul Sears        Ottawa, Canada

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