Didn't work for me when I tried it. =/ Then again the woman wouldn't let me take some of the gravel and she wouldn't go get the filter media and shake it in the bag. It took MAJOR convincing just to get her to fill up a bag with water from the female betta tank. =/ But then my petsmart just sucks more than your average one. =/
Also it might introduce disease in your tank. That's what I heard anyway.
Do you live near an ACE hardware store? If so then try buying some of their pure ammonia. =]
Or if you want to make it a lot easier on yourself I recommend SafeStart by Tetra Co. The cheapest place to get it is here: http://www.petblvd.com/cgi-bin/pb/TTR77960.html
There have been a ton of positive reviews for the site so I think it's safe but I'd still use a paypal if you're able. =]
That's where I'm getting it when my bank stuff is straightened out. =]