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Re: Seachem Flourish Question
>I had a question for you as well: Why did you think that the cyano
>problem might be attributable to low nitrate levels? By cyano I
>assume you mean the blue-green "algae"? According to Baensch Atlas
>volume 2 pg 162, the blue-green algae aka cyanobacteria can flourish
>in the following conditions: strong sunlight, rotting substrate,
>excess feed, too few water changes, overfertilization or _high
>nitrate levels_. If you are having a cyanobacteria problem I suspect
>one of the other conditions to be the cause since you report that the
>nitrate levels are low.
Baensch really isn't a good reference for this subject. Blue-green
algae can fix atmospheric nitrogen, so their dominance becomes favored
at LOW nitrogen levels, not high. As I posted earlier, blue-greens are
favored when the N:P ratio becomes low (less than 16:1), while the
growth of diatoms and green algae are favored at high N:P levels. Thus,
when P is in abundance and N is low, you can generally expect an
outbreak of blue-green algae.
This has been known among phycologists for years--I have a reference,
from a peer-reviewed journal, stating this back in 1979, and it has been
replicated by many others since. Strong sunlight doesn't cause a
blue-green outbreak, either, nor does a rotting substrate. Blue-greens
do not benefit from H2S, or CH4.