are the tops pressure sealed? If not just glue it back together. If its acrylic just use weld-on for it. If its not under pressure and its just a cap on it you should be to glue it with some time of cement and then be able to use it.
If its acrylic and its a clean break Weld-on will fix it and I wouldn't worry about a leak. This of course is me personally. I have never seen how they are put together so I can't really answer for you. any pictures of what happened?