Wal-Mart, Home Depot, Lowe's or any other place that might carry pool supplies. You will most likely need some PH down as well. You can find that at a pet store or anywhere else they carry aquarium stuff.
more like fuckin awesome. it has expanded my mind so much more. i never grew b4 this little seedling. she has changed my life. now i have more seeds germing. and i just planted another yesterday