i would use stronger baffles. i used cutting boards from walmart. they are very strong. the only problem is-they aren't transparent, they're white. you can have glass cut which will work well, and are the popular choice for baffles.
am i reading correctly, that the baffle broke, or was it the actual sump? if the sump broke, were the baffles too tight to the sump walls? i ran a bead down the walls and bottom of the inside of my sump, then placed my baffle against it, then ran another bead on the other side to seal it from both sides. i didn't force them into position. i had a tiny bit of space between the walls of the sump and the baffles, which got filled with silicone. hope that helps.