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Plants, Algae, CO2, and PH
This is my first mail to this list, so let me say that I've enjoyed reading
what everyone has to say. It's been very, very informative, though I'm
certainly not going to say I understand all the chemical reactions you guys
talk about...
Now the reason I'm posting:
I have a well-planted 55-gallon community tank with about 20 fish (not counting
the krib babies) and the following plants: Hygrophila Polysperma, Crinum
Thaianum, Echinodorus Maior, E. Amazonicus, E. Tenellus, a couple of Aponogeton
Undulatus, Ludwigia Repens, Cryptocoryne Crispatula, C. Becketti, Water
Wisteria (?), and one plant that I haven't ID'd. There are two filters on the
tank - a Whisper on one end and a BioWheel on the other. Lighting is two 33
watt flourescents. (I'm not sure of the brand. The lighting fixture holds two
48" T-8 bulbs, which are currently impossible to find in Atlanta, so I mail
ordered them from some place in California. It was the only place I could find
that had 48" T-8's.) These bulbs are on approximately 12 hours a day. Also,
at least 30% of the water is changed each week and a half.
And I also have a big algae problem. In fact, it's the algae from hell. I'm
99% sure it's the black brush algae pictured and discussed on page 166 (I
think) of the Baensch Aquarium Atlas, Vol. 2. This stuff just does not come
off. I have two large pieces of driftwood in the tank, and I've used a
toothbrush on them to try to get this stuff off with no success. Initially, it
took over one piece of driftwood, then migrated to the second piece, and now
it's started on the plants. Just on the edges. The Crinum has it fairly
badly. The E. Maior and E. Amazonicus are both looking pretty ragged. It's
also on the E. Tenellus and the Ludwigia Repens. Obviously, I've got to get
rid of this stuff or the plants are going to suffer more than they already
have...
I've tested nitrates and phosphates (Tetra kits), and both are low to
non-existent. I recently added Phos-Zorb filter media to the Whisper filter,
hoping that the phosphate test was incorrect and that this might have an
impact. So far, no impact. Algae eating fish don't seem to be the solution
either - the pl*co, Siamese algae eater, and five Otocinclus don't touch this
stuff...
The Baensch atlas says adding CO2 is the solution to getting rid of this
stuff. Why? Will adding CO2 increase the photosynthesis of the plants,
thereby increasing their need for nutrients and cutting off that available to
the algae? Or does it just not flourish in a high CO2 environment? And if the
CO2 does have an effect, is it too late to save the leaves already infested
with the algae?
I have a PH of around 6.2. I began DIY CO2 injection over the Memorial Day
weekend, so I suspect that it's now lower than that (the Tetra kit goes down to
6.0). I also included baking soda in the mix to try to buffer the PH
somewhat. The only CO2 kit I can find is a Tetra, and I've read that they
aren't accurate, so I haven't tested CO2 concentration yet. Using a Tetra KH
test kit, the KH is non-existent as well (the solution is never blue, even with
the first drop).
The CO2 airline is placed so that the bubbles enter the intake tube of the
Biowheel. You can actually see smaller bubbles of what I presume to be CO2
coming out of the Biowheel. The tank is stocked with mostly S.A. Cichlids, and
they don't seem to be too bothered by the PH drop associated with CO2
injection. I can see what I hope to be O2 on the leaves of some of the taller
plants. The low growing plants don't have this, however. And the O2 or
whatever is not streaming to the surface as I've imagined truly healthy and
happy plants with CO2 injection would do - it's just on the leaves.
Since I began CO2, the algae has turned a lighter shade of green (please tell
me it's dying). The Crinum, Hygro, E. Maior, Ludwigia, and Water Wisteria seem
to be responding favorably growth-wise, but they still have the same amount of
the algae on them. The other plants, mainly low-growers, show no appreciable
change. On the other hand, the fish seem none the worse for wear and tear.
Any suggestions for killing this algae from hell and saving the plants would be
most appreciated. Also, any suggestions for improving the CO2 injection method
would also be welcome. I'm also interested in suggestions for stabilizing the
PH at around 6.6. Thanks in advance.
Todd
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