My closure dilemma was solved with this baby: Recapitulation! Say that ten times fast. My regular algebra kids were impressed with such a huge word. Some even practiced pronouncing it correctly and showed off their skills to me. It was pretty funny.
Anyways, back to recapitulation. At the end of each lesson, I put up a question or a prompt that is meant to "recap" the lesson. I have asked students to list the important facts of a lesson, solve a problem, explain a process, think of a headline to summarize the lesson, and write potential quiz questions.
So far it seems to be working. All, except two or three students, are able to complete the recap by the time class is over. I've had to adjust my teaching, and I now force myself to end about ten minutes early. I have yet to see any results (i.e. test scores), but I will know soon enough if this is providing extra reinforcement or not.