Aquatic Plants Digest V1 #179

>I wouldn't become overly alarmed and "freak," but then again, I would
>take this seriously.  The appearance of Blue-Green Algae means
>that something is wrong in your conditions in either the water quality
>(conditions) or lighting.

I have experienced severe outbreaks of blue-green algae (cyanobacteria) under
the following conditions:
- Nitrates less than 10 ppm (heavily planted, with co2)
- 160 watts of fluorescent light (tritons and ultratrilux)
I don't have a phosphate test, so it is possible I had a problem in that
area, but basically I don't agree that it is as simple as water quality or
lighting. It seems that certain conditions help it get a foothold, but
once established it just takes over. Erythromycin will take care of it,
but I haven't found a sure way of preventing it.