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Cyano Preliminary Results/long
As you may or may not be aware I've been doing some research on 'green
water' or Cyanobacteria. I got about 25 responses and data on perhaps 30-35
tanks. Thanks to all who've responded thus far, if you haven't yet it's
still not to late.
Here the data in the most unscientific format could think of, if you can
think of a less scientific way to present this let me know.
1. When did the bloom occur? Almost all of the replies that indicated a
month or time of year indicated mid to late summer. This would indicate to
me that an elevated ambient or water temp can be a factor in establishment
of the bloom. I think there may also be a greater presence of "our"
bacteria around then.
2. What didn't/did cure it. There was an incredible amount of overlap
between these answers. There was absolutely no correlation between a cure
and a non cure. Some tried everything methodically for months while others
simply lowered feeding for a few days and had it disappear. Some contacted
me to say they'd kept planted tanks for decades and never once had the
"aquatic clap" and it must be the unseemly habits of the less virtuous
aquariest that brought it on. Simply put, nothing works and everything
does, some micron filtered for months and others cured it after 2 days of
filtering. Some used UV and others blocked light, all with the same dubious
3. Is it "new tank syndrome"? It definitely could be, but not always.
There was a high incidence of this, but not totally correlative. Anyway how
new is a new tank? Most, was new tank, 4 or less months old.
4. How long did it last? An average of about 2 months I'd say. Some as
long as 5 and running and some a week, but in general two months.
5. Did it recur? No, by and large not. I had some difficulty in deciphering
these answers but controlling for people who did a 70% water change or
micron filtered only to have it grow back, only in a couple of cases was the
tank re infected. A re infection is classified as a tanks that was clear
for months becoming cloudy again.
6. Water chemistry? All can apply, from hard to soft, basic to alkaline and
pure to polluted?
My thoughts are as follows. A new tank is especially like a blank slate.
The cyano moves in and establishes dominance. Much of cyano is toxic and if
present in large enough quantities may preclude other microorganisms from
moving in. This could be a form of aleopathy (sp?). Anyway, the system
marches on until the cyano ether chokes on it's own waste, which may not be
toxic to anything else, or until it reaches a limiting nutrient, this could
be something weird like manganese or copper or something we'd suspect like
PO4. It may be different for different cyanos because there are thousands
of species. At some point in this, but I think when the cyano is week, a
competitor or a pathogen moves in. There are viruses that prey on cyano and
they, like us may be more susceptible to attack at certain times. Once the
competitor or pathogen moves in, then it's all over but the shouting. The
normal healthy "balance" occurs and the cyano is competed against or killed
at a rate that we can accept, because our tanks stay clear.
What are my recommendations? UV filtration seems like it might work, and
has in the survey, because perhaps the balancing bacteria may be present and
growing in the substrate. Better than that though I'd say a massive water
change from a tank that was infected and is now "cured" or "inoculated", a
handful of gravel wouldn't hurt either. Don't set up your tank in July.
I received a long and interesting reply from a Cyanobacteriologiest from
Perdue University, that seemed to further my suspicions but did not confirm
them if there's interest I'll post it here, or send it to you e mail me
direct. I plan to put a form on line so I can better control the data, and
do a longer term study, those who have sites they'd let me link off of, let
All direct e mail about this topic should contain Green Water in the title,
it's easier to spell than Cyanobacteria. Even if you didn't participate, or
if you did, and want a commerative post card, let me know and I'll send you
Thanks all! Comments welcome!