Not sure about Flourish Excel but Seachem in general has a very good product line. I found this link about Flourish Excel:
http://www.seachem.com/support/FAQs/...Excel_faq.html

Water Sprite is a beautiful plant to keep, is a nice grower and a very clean, neat looking plant.
Here in South Florida, we have Anacharis growing wild in the canals, its very invasive! The water management district regularly clears it from the canals with special boats that go through and rake it out as it impedes the water flow and drainage of the state if left unattended long enough!

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