Most aquatic plants need iron and potassium (potash ) added to the aquarium,
hornwort included.

Hornwort also needs a 2 - 4 month "resting" period, with the water temp of
2-8 C, at least every 16 months. In the wild, the water cools off every
winter, and it's well-adapted to the yearly cycle.

If you can't provide your hornwort a cold period yearly, you will need to
keep replacing it. It also grows best at temps betwen 18-22 C. 25 C is a
little too warm.

YMMV . Glad to help;
Limnophile

"Bill Stock" wrote in message
ers.com...
"Bill Stock" wrote in message
gers.com...
The tips of my Hornwort are turning brown. Any ideas?

PH 7.5
Temp 25C
Nitrates 20 ppm
Light 72W CFL (Double in winter)