Re: [APD] Dust algae with skunky smell

["S. Hieber" <shieber at yahoo_com>]

The malodorous stuff is often a sign of the so-called
blue-green algae, aka BGA, which is a cyanobacteria that
can spread quickly, had an unattractive odor and will grow
on top of other alagae. BGA usually has a more blue-green
color than the green dust that grows on the glass. Once it
gets going it tends to spread like a film and the "film"
can be lifted and pulled away for whatever solid object it
is holding onto.

While diff algae have diff odors, BGA is noticeably
unlikable as an olfactory experience.

You didn't mention potassium other than what's in the trace
mix. I would add potassium (potassium sulfate), about as
much as the nitrates you are adding, just on GPs.

If the growth is just the ordinary green dust that grows on
the glass, you probably have too much nitrate for the
amount of phosphate and potassium in the water. If there is
too little of one or both of the others, then the plants
are not able to use up all of the nitrates, which is a
condition the green dust algae seems to relish. It would be
worth checking if you have a good quality kit (e.g.,
SeaChem or LaMotte) that can measure nitrates in increments
less than 10 ppm. If the nitrate is too high, back down on
the nitrate dosing or up the dosing on the others to get a
ratio roughly 1:10:20 ppm for phosphates, nitrates,
potassium, respectively. Also, 1:10:20 is a good target for
levels of those macro nutrients.

It's a good idea to manually clean up as much of the algae
as you can just before each water change. Brushing or
scraping doesn't remove what is brushed or scraped from the
aquarium; it merely moves it off of the glass. But to the
extent that it becomes waterborne for a while, some of it
can be sucked out with a water change or get an opportunity
to ride the UV express ;-)  . Scraping alone is good for
cleaning the glass but it doesn't have much to do with how
much algae in your aquarium. Balanced nutrients and lush
plants seem the best thing for limiting algae growth.

The UV will kill the algae that passes by the bulb but
algae can still grow in the aquarium, release waterborne
cells that spread to other surfaces before all the water
passes through the UV. Thus, a UV can retard the spread of
waterborne algae but it won't eradicate algae in an
aquarium.

Hope that is some help,
Scott H.
--- Pete <peteal at sympatico_ca> wrote:

> Hello, just wondering if anyone knows what this is.  I've
> had for a long 
> time a green dust algae that grows along the glass of the
> tank, never been a 
> real problem and easily dealt with by a brushing with a
> cleaning magnet 
> every week or so.  I've also had some minor hair (the
> super fast growing 
> hairy ball clump stuff) algae in the tank but again no
> real problem (easy 
> removal).  But lately all the hair algae has gone but the
> green dust stuff 
> has come in with a vengeance, it comes back daily and now
> has a very strong 
> skunky (wet seaweed) smell.  Not sure if it's  a
> different variety of what I 
> had before but it's extremely quick in coming back. 
> Anyone else had this 
> smelly stuff and know what it is and how to slow it down.
>  Got a UV filter 
> attached and that slows it down but I don't like running
> it 7/24.
> 
> I've got a 90gal heavily planted tank with DIY CO2 (which
> does give me the 
> CO2 concentration target, 2 x 3L CO2 bottles changed
> alternate weeks :P) and 
> a medium fish load.  Dose with Nitrates and Phosphates
> every other day to 
> keep good levels along with TMG. Haven't done any recent
> tank changes.
> Might have been while I was away on vacation for a week
> but that was two 
> months ago.  I though the large building was just a weeks
> worth of dust 
> accumilated due to no cleaning and less fertilization..
> but it's been bad 
> ever since.  I don't mind some algae (from what I've seen
> it's harder with a 
> good fish load to eradicate) and never went on a crusade
> to get rid of it 
> all but this one is getting annoying.
>

=====
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