Re: [APD] Barr Method Question

[Andrew McLeod <thefish at theabyssalplain_freeserve.co.uk>]

On Fri, 5 Dec 2003 15:11:25 -0800 (PST), S. Hieber <shieber at yahoo_com> 
wrote:

> It would seems that holds only if the only nitrate source,
> for example, is the chems you're dosing. Lots of fish,
> complicates things and the frequency matters, just in the
> sense that, if you wait too long between changes and the
> nitrates keeping climbing, well, the inevitable end isn't
> pretty.
>
> Scott H.
>
> --- Andrew McLeod
> > The frequency of your changes is irrelevant to the final
> > level of nutrient
> > you will have AFTER each change
> > and fertilisation, but to avoid spikes change water
> > regularly.
>
> =====
> S. Hieber

That was the (horrendously inaccurate) assumption I was making. But if you 
were adding 10mg, and the plants took away 6mg per interval of water 
change, then you could simply assume you were adding 4mg and the method 
would work. Presumably by maintaining a constant nutrient level level, 
constant fertilisation and regular measured water changes you could find 
the amount added/removed by fish/plants per unit time.
I was about to ask how much nitrogen fish pooped and plants removed, but 
then I realised that nitrogen inputs (food, fertilisers) must equal 
nitrate out (water changes, plant matter), if you could that out.
That's assuming that aquatic plants don't absorb atmospheric nitrogen, 
like terrestial legumes (says my hazy knowledge of GCSE biology). Do they?

--
Andrew McLeod
thefish at theabyssalplain_freeserve.co.uk
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