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Re: [APD] Barr Method Question

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

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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