I've never used that form, so I can't offer advice. Try going to this web site, and looking for a dealer near you. Give them a shout and see if they have (or can get) powdered aluminum sulphate. If not, call a farm fertilizer supplier, or your counties farm co-op.

http://www.helenachemical.com/locations/Pages/locations.aspx

www.hoosierpondpros.com

[Linked Image from lh6.ggpht.com]
http://www.pondboss.com/subscribe.asp?c=4
3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).