After having both stick-on weights and an epoxied weight come loose after several years, I switched to silicone caulk and have had no problems since. I also looked at why those weights came loose and decided it was the application as much as the adhesives. The inside of most resin floors is almost as smooth as glass giving any adhesive nothing much to grab on to. I've started sanding the inside surface with rough sandpaper to give some tooth to it. I think it will help.
