Overrun By Algae: Have At Thee, Epiphytic Terrors!

[Chuck H <grendel at usit_net>]

I woke up and it's raining.  There goes my plan of hunting for native 
plants and fishes today.  So I'm sitting around bored and I thought I'd 
share the story of my latest and worst battle with algae.  What I observed 
makes Tom Barr's hypotheses concerning the competition between plants and 
algae seem very much on target.  But it's no surprise to me that Tom would 
be on target.

A note for the algae afflicted:  This post is not meant as a how-to for 
killing off an algae plague.  Some of the things I did worked to varying 
degrees (most didn't!), but I feel I was lucky as much as anything.  What 
worked for me may not for you.  But I do hope my experience will encourage 
patience.  It's the most valuable tool any aquarist can have.  I also hope 
my story will illustrate how wrong things can go if you get cocky and careless.

So here's how it went down...

Around the first part of December, I replaced the filtration on a small 
tank (20H) and also stirred up the substrate real good with a heavy 
replant.  I knew better than to change so much at once, but recent 
successes had left me drunk with confidence.  The result of the 
changes?  NH4 aplenty.  Predictably, algae exploded and much more 
virulently than I have ever witnessed due to not only the NH4 but also to 
my rather reckless addition of a sizeable amount of triple superphosphate 
(TSP).  This took place during my brief "experiment" phase (which I'm 
happily over now) and I was trying out various terrestrial fertilizers, but 
I digress.  The replant and addition of the new filter took place on one 
day and the TSP was added the next.  Within 12 hours of the addition of the 
TSP, it was obvious something was very wrong.

Other than an odd odor which I'm unable to articulate and the appearance of 
surface film, the most immediate symptom of trouble was the abrupt 
cessation of pearling by the plants.  DO crash?  Maybe, I didn't test.  I 
swear that the tank looked like it had a storm cloud over it -- you know 
that surreal look that things get just before a bad storm?  The next 
obvious symptom was the rapid melting of Cardamine leaves.  I'm still not 
sure what that was about, but it may have been a PO4 overdose.  Next came 
the explosion of algae.  The worst offender was a pelt alga sp. that is 
probably an Oedogonium but possibly Pithora.  It dominated practically 
every surface in the tank within a few weeks.  Black Brush, Staghorn, and a 
long hair (Cladophora?) also grew in abundance.  The tank really looked 
like hell.  I removed tons at a time but it filled right back in.  It was 
so bad I had to remove the fishes because they were obviously getting 
cramped and uncomfortable and I couldn't get food through the webs of algae 
to bottom feeders.  When I say the algae was bad, I mean horrible.

Well, I was bummed out, but I looked at it as an opportunity to play with 
the algae (I'd never encountered pelt/fur algae before) and hopefully learn 
a few things along the way.  I'll spare you most details of my fooling 
around, but here's how I eventually got each alga sp. under control:

The Black Brush and Staghorn were very easy to wipe out.  It was a simple 
matter of water changes and getting nutrients, especially CO2, back in 
line.  Both algae tried to hang on but disappeared fairly quick.  This 
didn't surprise me as I've dealt with them before and their presence in my 
tanks is almost always due to a problem with CO2 -- I was using DIY.  The 
hair and pelt algae were another matter and continued to grow like mad; I 
hate flagellated alga cells!  The only bright spot was that the higher 
plants were still growing some at this point.  But they were being swamped 
rapidly.

I tried a number of things to break the remaining algae, but nothing 
significantly harmed it.  By this time (~ late February), the plants were 
nearing a breaking point and new growth was rare.  It was crunch time.  I 
began considering breaking the tank down and trying Paul's bleach dip 
method.  But I still had one last card to play; I took my DIY CO2 bottle 
and yanked it up and put a high-pressure setup in its 
place.  Bingo!  Within a week or two of a *consistent* CO2 level of 21ppm, 
it was obvious the algae was in trouble; algae growth slowed to a 
standstill, plants began putting out new growth above the dense carpet of 
algae, and this new growth remained clear of algae.  The algae itself, both 
types, turned from a healthy green to a nasty looking grey-green and began 
fading away, but some patches persisted though they were not 
spreading.  The final deathblow came about a month ago when I upped trace 
element dosage significantly even though I had already been adding above 
label recommendations.  I don't think the extra nutrients would have helped 
had I not had that rock-solid CO2 going, though.

Now, after about 5 months since the onset of the algae, there is little to 
no visible sign of algae and the tank is in full recovery.  Plants are 
pearling and growing well (some actually better than before) and even the 
driftwood is clear and clean looking.  The water's surface is film free 
once again and the fishes are back in their home.  Perhaps the most amazing 
thing is that the leaves of the plants, particularly Anubias, that were for 
months covered in dense fur now look just as clean and beautiful as they 
did before the onset of the algae.  I had been certain that they were 
goners.  In the end, the algae only took a few sword leaves, a baby sword, 
some moss, and a few stems of Cardamine.  What actually caused the pelt and 
hair algae to die off is probably a complex of things, but I'm certain the 
addition of a stable CO2 source played an important part.  The algae war 
may still rage, but I won this battle.  Stick that in your rubisco and 
smoke it, algae!
--
Chuck Huffine
Knoxville, Tennessee