Re: Confusion/questions on dosing Seachem Nitrogen...

[Chuck H <grendel at usit_net>]

Jeff wrote of Seachem's Flourish Nitrogen:

>Directions state:
>
>"DIRECTIONS: BEGINNER: Use 0.5–1 mL (dispenser enclosed) for each 80 L (20
>gallons*) twice a week. EXPERT: The beginner dose raises nitrogen by the
>same degree that 0.45–0.90 mg/L nitrate would. This dose is sufficient to
>provide approximately 4 g of growth (dry) or about 20 g (hydrated) over a 1
>month period (assuming all other necessary nutrients are provided). For
>increased growth use proportionately more. To target a specific nitrogen
>increase, dose according to the following formula: 0.25vn=m, where v= volume
>of tank in gallons*, n=desired nitrogen increase (for a desired nitrate
>increase use a factor of 0.05 instead of 0.25 in the formula) and m=volume
>of product to use in mL. For example to raise 20 gallons* by 0.20 mg/L
>nitrogen you would use: 0.25*20*0.20=1 mL. (For 2 & 4 L containers, 1 capful
>is 10 mL)."
>
>Now, onto my problem and where the confusion arises...
>
>I want to keep approximately 5ppm of N available for plant intake.
>
>According to my estimates, should I use the beginner dosage in my 50G (55G -
>estimated gravel volume) tank, I would add about 2.5ml twice per week. Or as
>I read it the beginner dose yields almost 1ppm of available N (added twice
>per week) - hardly anywhere near a sustained level of 5ppm.
>
>Drawing a straight line from here (the beginner dose) to get a 5ppm N would
>mean I would add 5x this amount, or 12.5 ml (assuming of course that N
>depletes over the week or at water changing time) twice per week, or 25 ml
>per week.
>
>IF I follow the "Expert" directions, to reach a 5ppm of available N, I would
>use the formula:
>0.25vn=m - For my tank and 5ppm desired N this reads
>
>0.25 x 50 x 5 = 62.5 ml initial dose.... Wow, am I glad I bought the 2L
>bottle!!!
>
>And 12.5ml (or 25ml using the 2x dose per week) is quite a ways from
>62.5ml... Does anyone have any practical experience dosing this stuff
>(assuming a medium-heavily planted tank...).


You're on the right track, but remember that you're after the equivalent of 
5ppm NITRATE.  The "expert" formula yields the dosage required to achieve a 
specific level of NITROGEN, not nitrate.  So, you should use a factor of 
0.05 instead of 0.25 in the formula to determine nitrate (0.05vn = m).

During the beta test, I simply divided the result of 0.25vn=m by 4.4 to get 
nitrate equivalency.  This method yields a slightly higher number than the 
formula 0.05vn=m does, but either way should work fine.
--
Chuck Huffine
Knoxville, Tennessee