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Re: NO3 and PO4 in Takashi Amano Aquaria

Tomoko Schum has provided a lengthy explanation by Takashi Amano for the
nitrate and phosphate levels in two tanks, pictured and described in a
recent TAG article. NO3 was indicated as 1 mg/l or less, and PO4 was said
to be 0 mg/l.

> The translation of the nutrient related parameters in the articles that
> appeared in TAG is correct.
> <snip>
> As far as PO4 readings of  0 mg/l is concerned, this has something to do
> with the accuracy problem of the test reagent that we were using in the
> past.  This particular reagent is capable of measuring PO4 in the range
> 0.2 to 10 mg/l. ...However, when aquatic plants start absorbing PO4
> rapidly, PO4 would no longer be detected with this reagent.  There was a
> period we misjudged the PO4 level to be 0 mg/l because of this
> However, since PO4 can be detected with a more accurate reagent, we now
> use the notation of <0.2mg/l when we can barely detect PO4 level with
> reagent.
> <snip>

I can certainly sympathize with the difficulty of making PO4 measurements.
I use a LaMotte low range kit and have always had trouble making color
matches at low levels. Furthermore, one of the two reagents has a shelf
life of only one year, after which it fails to indicate any PO4 at all. To
make matters worse, if you buy fresh reagent from LaMotte, you run up
against a $25 minimum order requirement.  And, even worse, if you buy
reagents from distributors, you will find that they have either already
expired or, as in my most recent purchase, are already six months old!

> Generally speaking aquatic plants grow better when the levels of
> such as PO4, NO3 and K are abundant.  However, since algae grows better
> such a condition, we maintain PO4 and NO3 in water column as low as
> possible.  If some fish are kept and fed every day, PO4 and NO3 would
> be
> lacking in our opinion.
> <snip>
I feel much reassured by this explanation and would also like to thank
Tomoko Schum for the effort it must have taken to obtain the information
and then to translate this lengthy explanation so clearly for us.

John T. Fitch
E-mail: JTFitch at FitchFamily_com
Web Site: www.fitchfamily.com/aquarium.html