I don't know about the one you used,but the puties and 5 min.epoxies available at hardware stores,are not water resistant!
Here is my experience with adhesives:
- For corals they primarely use super glue gell,but didn't work for me (as others mentioned above).I even had originally attached shroom to a shell and glued the shell to a rock and the shroom just left the sight( slowly,within days).
- To attach rocks,use the bond-fast putty form lfs.It hardens under water,but tie the things down for 24 h not to move.Than is hard enough.
- For DIY projects I used 5 min. Epoxy syringe # 12 (from Lepage).This is the only one water safe,the others will bond,but within weeks,will release the surface.
My oppinion is that if it doesn't say on the product that's water resistant,it isn't.
Good luck
FM