Cathic
Fish Wrangler
You could try making a clamp brace to run across the buckets, as inevitably they will bow some (maybe not enough to notice but definitely enough to stress the bond between baffle and tub). Remember without the brace the entire weight of the water expanding against the walls of the container go straight to the spots that connect the two sides. You could also try double gluing and run the silicone (or whatever you are using) down both sides of the baffle (as opposed to line and insert) to create more contact area between the container and the baffle.
Just my 2c
Just my 2c