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Re: Iron Levels

> Date: Wed, 28 May 1997 14:48:40 -0400 (EDT)
> From: STDIXON <stdixon at bechtel_com>

> [...]
> My recent experience (say 6 months or so) has been that using enough PMDD
> (made according to the Sears/Conlin recipe) to achieve 0.1 ppm iron
> consistently results in hair algae and a darker brownish algae covering
> leaves of many of my plants, especially swords, anubias and h. difformis.

> Sometimes the algae has been quite severe, yet the iron levels remain
> 0.1 ppm.  [...]

Just another data point here. I have also experienced the same two kinds of
algae with Dupla24 + KNO3 fertilization. My iron levels range between .05
and .1ppm. I fertilize with KNO3 to a NO3 level of about 4ppm.

The hair algae in my tanks is a very light green, mushy-feeling or soft to
the touch, few-inches-long alga that is manually removable without damage
to leaves. It does not appear to fork, and seems to exist nearly entirely
anchored to leaves or glass. I have been told this is Cladophora. The
darker algae on leaves is a tougher encrustation. It reminds me of dead
cyanobacteria; my tank in question does have cyanobacteria in the
substrate. This second species is also manually removable with some
difficulty, but this is rather a pain to do to a two square foot bed of
Lilaeopsis as the twirling toothbrush removal doesn't work.

I am interested to see whether the tank is really iron-limited when the
iron levels drop, so I will lower the Dupla24 fertilization rate in this
tank and see if the algae problems lessen and if plant growth slows. (Note
to anyone who does this: If you do reduce the trace mineral input, monitor
nitrates very carefully, because if the plants' metabolism does slow down,
their nitrogen uptake will slow down as well!)