I agree. Even if you repair it, I'd always keep it internal to a sump/fuge or whatever.
I have an ER CS-12 that was "repaired" when I got it. I've used some Weldon 16 (I think) to bond the pieces back together. But I don't think it will ever be the same strength as original. It's really not that hard.
My crack was around the drain tube. I managed to also build some support the tube. If that's the pump inlet, it may be more difficult to support the weight of the pump. Make sure that somehow you support the weight of the pump and don't let it just "hang" it's weight on the mended acrylic.