"Richard" wrote in message ...
In article ,
Chameleon wrote:
I started a 20 gal CO2 injected (DIY) planted tank about 3 weeks ago and
I've been monitoring water chemistry and plant growth very carefully.
There
are currently no fish in the tank, althought I will add some later to get
it
cycling properly. The substrate is layered. 2:1 perlite:soil + a fine
gravel overlayer. All my plants are pearling beautifully and growing at
anticipated ridiculous rates. Good root structure developing too.

I have a couple of sword plants in there. One of them is still sending
out
the "pre-maturity" broad leaves rather than the narrow sword leaves of
later
plant life. I have noticed that on one of the newest leaves, the entire
leaf is healthy looking, but almost totally brown.

Add nitrate.

What is it that I am seeing? Nitrate deficiency, duh. But why does that
make the leaf dark?