Sorry to hear about your loss and the problems. The good news is bad things come in three (broken heater, stuck heater, dead fish)...so you should be done now.
Sorry to hear the bad news, but that is the reality in this hobby . I wish it wasn't though. All you can do is learn from bad and good experiences. Good luck,
Pete
I had a glass heater break in my 30g. I happend to be looking in the tank and seen the flash, before I could do anything it exploded. I lost a few fish too.
I've had a few heaters break, many years ago... mostly because the Idiot I was would do a water change and forget to kill the heater, then refill the sump and the glass would cool to fast and crack... However, the sump is an easy clean, whereas the display would be much much worse!
I once touched my wet arm to a halide bulb to have it literally exploded. It sounded like a shotgun going off in my ear! glass flew everywhere including into the tank.
I never have liked the idea of separating water and electricity with glass... unbreakable heaters and LED's are life savers...
Ok, feel a little better today, maybe might even take some pics later if everything opens. 5 hours of water changes, dipping corals, scraping, pulling, and cleaning the tank looks better than it has in a while. still needs some work but better. Ill check nitrates and hope they have come down by half at least.