From: rclark@alcor.concordia.ca (Richard Clark)
Subject: (Summary) Erythromycin vs Blue-Green Algae - a short article
Summary: please review my (non-profit) article for inaccuracies
Keywords: blue-green algae, plants, anti-biotics, erythromycin
Organization: Concordia University, Montreal, Quebec
Date: Tue, 17 Nov 1992 09:29:54 GMT

Hi,
This may be asking a lot, but in the brief article I wrote below I
tried to summarize some of the information I have read on the net
concerning blue-green algae.  In a couple of places I refer to
``someone'' saying something on the net, if you know who said it I'll
be glad to credit the person in the text.  I wanted to reference
George and Karla Booth's recent series in AFM as a good place to get
information, but I don't know what months it ran (or is still
running).   Could someone tell me?

I will submit the article to a local aquarium club bulletin (only
non-profit places), not to any fishy mags - as if they'd accept it.
If someone wants to use it I don't mind as long as I'm informed.
Since the material is largely summarized from the net, I was hoping
someone would take the time to read it, and point out any inaccuracies
that may be present.  It is approx 140 lines of text in LaTeX, but
readable by non-LaTeXperts.  LaTeXed, it is slighly less than 2 pages.

Thank you

rick clark

----------------------------------------------------

\documentstyle[twocolumn,11pt]{article} 
\title{Battling with Blue-Green Algae} 
\author{\copyright Richard Clark, Montreal Aquarium Society
\thanks{May be freely distributed or reproduced only for
non-profit use, as long as no modification is made to the text, title,
or this notice.  Montreal Aquarium Society, P.O. Box 653, Station B,
Montreal, Que. CANADA, H3B 3K3}}

\date {November 8, 1992}
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\addtolength{\textwidth}{1.5in}
\addtolength{\oddsidemargin}{-0.75in}
\addtolength{\evensidemargin}{-0.75in}
\addtolength{\headheight}{-0.5in}
\pagestyle{empty}

\begin{document}
\maketitle
\thispagestyle{empty}

If you have a heavily-planted fish tank, you know that your worst enemy
isn't ich or fungus - it's algae.  Typically, the fish in the tank
cost far less than the plants.  It's a crime what a little neglect
can do to a well-planted tank.  Miss a few water changes, add a
little pH buffering solution to your water, have strong light, use
some plant fertilizer, and chances are you'll be looking at algae that
will cost you plenty of green stuff.

It has happened to me. I used fertilizers as recommended on the
packages, added Wimex iron supplement, had 2 20 W fluorescent tubes on
top of the 75 $\ell$ tank, and had pretty good plant growth.  My
Apongeton crispus were flowering, my Echinodorus bleheri were
flowering -- I was on top of the world.  Then it happened.  A dark green algae
started to cover some of the plants.  I thought - ``no sweat'', I bought
the algecide from Aquarium Pharmaceuticals, placed the recommended
amount into the tank, and watched my fish (mostly tetras, but also a
plecostamus) go crazy trying to jump out of the tank.  I rapidly did a
50\% water change which seemed to calm the fish down, and did another
50\% water change the next day.  I noticed that the nice green algae
was dead, but the ugly stringy stuff and the dark green slimy stuff
was doing great. Algecide was definitely not the right treatment.

I tried the ``old-fashioned'' approach to reducing the algae - I shut
off the lights for a few days. The Hygrophila polysperma, already
weakened by the algae, all but died and I had to pull it out of the
tank.  The A. crispus died back, and I had to pull off numerous leaves
from the E. bleheri.  I now only had about 1/3 of the plants I
originally had, but I was reasonably algae-free because I had thrown
out everything with algae on it.

Over the next few months I purchased a few more plants, including some
from the club auction, but unknown to me, those had algae on them.
Guess what?  I was in trouble again.  I didn't notice it at first
because the algae was close to the stem on my cabomba and not on the
leaves where it would be easily visible.  This time I tried a more
systematic approach, I used my computer to find help.  I have access
to a world-wide network of computers (Internet), and read
``newsgroups'' about tropical fish. One guy reported that the dark
green ``algae'' one sees in tropical fish tanks is not really an
algae, but a bacteria. He reported great success in using the
anti-bacterial drug erythromycin (available at pet shops, trade name
for it is Maracyn - not Maracyn II).  In fact, blue-green algae are
not bacteria, but share many of their characteristics \cite{Bake77}.
Erythromycin works by attacking the cell wall of the bacteria
\cite{Dixo92}.  I figured I didn't have much to lose, so I bought
some, removed the carbon from my filter, used the recommended dosage,
and miracle of miracles, the ``algae'' died off without affecting the
other plants or fish.

The miracle cure wasn't without drawbacks though.  Although the
instructions on the package specifically state that Maracyn does not
affect Nitrosomonas and Nitrobacter bacteria (those responsible for
the nitrogen cycle in the tank), I immediately noticed a rise in
ammonia levels.  The depletion of nitrifying bacteria by erythromycin
is also reported in \cite{Dixo92}.  I used Amquel to remove the
ammonia, and continued to use it until water changes reduced the
amount of erythromycin in the tank, and the filter was again working
properly (about 2 weeks). Through interactions with other people on
the internet, it appears that freshwater nitrifying bacteria suffer
more than saltwater ones from this treatment, but this is only a
casual observation and I'm not ready to commit to that statement yet.
I'd be happy to hear about your experiences to see if this theory is
correct.

Over 100 varieties of blue green algae are found all over the
world\cite{Bake77}.  It's hard to avoid getting any in your tank
because the spores are in the atmosphere, and  plants you put in the
tank are likely to contain some.  Although high nitrates are usually
suspect when blue-green algae begins to grow, Vinny Kutty reports
\cite{Kutt92} that it can grow even in water that is almost absent of
nitrates (because it can fix atmospheric nitrogen) -- provided there
are phosphates in the water. Kutty reports that a level of 0.5ppm of
phosphates in a river is considered ``polluted'', but that phosphate
levels below 0.5 ppm may retard plant growth.  My guess is that a
level somewhat below 0.5 ppm would be a good target for phosphates, and
about 10 ppm or below for nitrates (freshwater). 

There are a couple of ways to keep nitrates and phosphates at low
levels.  You can either try to keep their introduction to the tank
low, or you can get them out of your tank once they are there.  In the
latter category, there are of resins that can be used and the old
standby -- water changes.  To make sure the phosphates and nitrates
don't get in your tank, note that many plant fertilizers contain these
components, so use them sparingly (see below).  If you use a product
that buffers the pH of your water, it likely contains phosphates.
Novaqua, a common water additive, will result in 5 ppm phosphates if
used as directed.  Overcrowded tanks are a cause of phosphates from
fish waste \cite{Kutt92}, and of course, with a working biological filter,
ammonia is eventually converted to nitrates.  PH Down, a product which
lowers the pH level of aquarium water uses phosphoric acid, so that
might not be a great idea either. Finally, check your water supply, it
may be the source.

I don't want this article to be a complete downer regarding keeping
plants, so I'll just summarize quickly some of the points I have
gathered from my internet reading.  Fertilizers are not generally
recommended in planted tanks because of the potential algae problems.
Trace elements and iron are all that should be used, fish provide the
rest of the fertilizer.  You must provide sufficient light for the
plants to grow, this is the most common problem people have with
plants. About 40 W of fluorescent light on a 75 $\ell$ tank is about
right \cite{Jame88}.  I use one full-spectrum bulb and one
``plant-bulb'' on my tank.  You have to provide sufficient gravel for
the plants to grow, about 8-10 cm of 1 or 2mm gravel is okay.  Water
changes are important, they help to reduce any pollution that may be
present in your tank.

I wish you luck in keeping your plants healthy, use the guidelines
I collected above to try to reduce the chance of algae infestation in
your tank.  If the choice is between losing your plants or using
Maracyn, use it, but keep a close eye on the ammonia level.  Don't
depend on using this drug to combat all algae, just blue-green algae.
Remember that using anti-biotics on a casual basis can result in
strains of bacteria that are resistent to the anti-biotic - so be
careful.  A few good references on keeping plants in an aquarium are
below.

\bibliography{/usr/fish/me/fishbib}
\bibliographystyle{alpha}
\nocite{Jame88,Baen91}

\end{document}

@book {Baen91,
 author   = "Dr. {R\"{u}diger} Riehl and Hans A. Baensch",
 title    = "Aquarium Atlas",
 edition  = "3rd",
 publisher= "Tetra Press/Baensch",
 address  = "201 Tabor Road, White Plains NJ.",
 note     = "ISBN 3-88244-050-3",
 year     = 1991
}

@book {Bake77,
 author = "Jeffrey J.W. Baker and Garland E. Allen",
 title  = "The Study of Biology",
 edition = "3rd",
 publisher = "Addison-Wesley",
 year = 1977,
 note = "ISBN 0-201-00349-X"
}

@article {Dixo92,
    author = "Dr. Beverly A. Dixon",
    title = "Antibiotics -- How do they work?",
    journal = "Aquarium Fish Magazine",
    month = feb,
    year = 1992,
    pages = "54-59"
}

@book {Jame88,
 author   = "Barry James",
 title    = "A fishkeeper's guide to aquarium plants",
 publisher= "Tetra Press/Salamander Books",
 address  = "201 Tabor Road, White Plains NJ.",
 note = "ISBN 3-923880-57-X",
 year = 1988
}

@article {Kutt92,
    author = "Vinny Kutty",
    title = "It's about Algae",
    journal = "Aquarium Fish Magazine",
    month = may,
    year = 1992,
    pages = "40-48"
}




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