be careful throwing it out...if it gets into your local waterways it is known to be an invasive species and can overgrow lots of native plants and play hell on an ecosystem.
also, if your stem plants aren't getting enough light because of it, you might want to take a second fluorescent bank and place it at the base of the tank, angled up and inward so that they get light from an unobstructed source.
So remember, when you're feeling very small and insecure,
How amazingly unlikely is your birth,
And pray that there's intelligent life somewhere up in space,
'Cause there's bugger-all down here on Earth.
Loki/Grendel/Gail/Beowulf/Camilla/River/Bathory/Arwen/Lafayette/Deb/Jack Skellington (soon)