You might want to add some strainers or guards to that piping. Or you will need another drain put in like emergency overflow. Also, if you have APEX, you might want to get the FMM/leak detectors or high water sensors at the sump...so it can shut down pumps if they detect leak or high water levels. And I think another reefer recently mentioned that they put pond liner in their stand to catch leaks. So you will have to build in multiple fail safes for this or it's going to happen again.
I do feel your pain though. I have an external chamber...that I'm weary of running. I'm going to have to put in some fail safes as well.