# Re: [APD] Need Help to Test my Test Kit

```Thank you so much for going through the trouble to provide this info. I'm so
glad that I did'nt try the calculations I was thinking would be accurate. My
attempt at this formulation looked nothing like yours, plus my eyes were
starting to cross. Thanks again.
PS. Who is Greg Watson (forgive my ignorance)? Does he sell the KNO3 you
speak of?
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Message: 6
Date: Fri, 21 Oct 2005 21:04:50 -0700
From: Vaughn Hopkins <hoppy1 at surewest_net>
Subject: Re: [APD] Need Help to Test my Test Kit
To: aquatic plants digest <aquatic-plants at actwin_com>

Ok, here's my calculation:
KNO3 = 1.069 gm/ml
K = 39% of KNO3
1 gal H2O = 3.77 liter = 3770 grams
20ppm = 20/1000000 =2 x 10-5
2 x 10-5 x 3770 gms (H2O) = .0754 gms (K)
.0754/.39 = .1933 gms KNO3
.1933/1.069 = .181 ml of KNO3
1 tsp = 4.93 ml
.181/4.93 = .037 tsp KNO3, which is a little more than 1/32 of a tsp.
Therefore:  about 1/32 tsp of KNO3 (from Greg Watson) in a gallon of
distilled water will give about a 20 ppm solution. (Actually, it gives
17 ppm, if you could measure 1/32 accurately.)

Who wants to correct my errors?

Vaughn H.

On Friday, October 21, 2005, at 06:18 PM, Charlie wrote:

>
> Can anyone offer advice on preparing a control sample to test my K
> test kit?
> I know many of you are familiar with Seachem Flourish. I'm trying to