Nope, you are on the right track. Sumbersed or emergent pond weeds are hard to find because there are very few suppliers. Try searching for J.F. New in Indiana. They might have some this Spring.

www.hoosierpondpros.com

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).