stargrass get burn mark at the bottom

[mad]

i have stargrass in my tank and the stargrass look ok on the top but not the bottom as it turn blank and a bit burn ...??how to get rid of the burn and propagate it to a healthy stalk??

[juggler]

There was a similar discussion at http://www.aquaticquotient.com/phpbb...ic.php?t=16978