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Re: Jonathan's tank

> Date: Sun, 14 Dec 1997 22:12:23 +0800
> From: "Jonathan Uy" <5js at durian_usc.edu.ph>
> Subject: nutrient deficiency?
> I have a 55g temporary holding tank with sand, soil and peat as the
> substrate.  The tank get around two hours of direct sunlight and lots of
> natural daylight for the rest of the day.  It has yeast CO2, PMDD but no
> nitrates added, very light fish load.

  If you are using PMDD, then you _are_ adding nitrates. Potassium
nitrate is one of the main ingredients of PMDD. Perhaps, you mean that
no _extra_ nitrates are being added.
> The plants are growing fast but I noticed that black lines or scratches on
> the older leaves of Stargrass develop.  This will soon spread and the
> entire leaf turns black.  The same thing happens on the old leaves of the
> H. Polysperma but instead of turning entirely black it begins to die
> resulting in a lot of premature leaf fall off.  My Echinodurus Paniculatus
> sometimes have brown veins on an otherwise healthy looking leaves.  The red
> plants are only half red.
> With no test kits yet, I hope somebody can help me identify these symptoms.

Stargrass, or Heteranthera Zosteraefolia, seems to be very sensitive to
being handled. It reacts to damage in the way that you mention above.
Some people have said that even a strong water current can cause these
injuries, but that hasn't been the case for me.
I believe that brown veins in the Echinodorus species indicate a
healthy, happy plant.
You said that the red plants are only half red. I'm not sure what this
means, but as a rule, red plants need quite a bit of light to develop
their best colors. The H. Polysperma, I have no idea about. Perhaps,
someone else can help you with that one. Overall, I wouldn't worry too
much. I don't read anything that seems to indicate a serious problem,
and too many nutrients in the water is just as bad, if not worse, than
too little.

Pat Bowerman