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Re:Re: Bacteria algae and N:P
At 03.48 12/01/2001 -0500, you wrote:
>What I *should* have said is:
>If you want phosphorus-limited conditions and have 5 ppm NO3, then you
>shouldn't let PO4 exceed about 0.2 ppm.
OK. But which P? and above all where?
I mean 0.2ppm of PO4 doesn't really mean that much to me. There are so many
kind of phosphates, and I'm not sure which kind can be assimilated by
plants and which cannot. Plus plants _already_ contain the P uptaken from
the water column, because the P uptake's rate is extremely fast! So what
you measure is the 'rest' of P still in the water.
Last week in my tank I measured:
0.000ppm of PO4 as ortho-phosphates
0.041ppm of PO4 as total phosphorus content (ortho + poli + organic phosphates)
and with N-NO3 content of 0.71ppm ...I *should* be in a P limited
situation, nevertheless I'm not surely in an algae free condition!
what do you think?