I stopped buying glass heaters just for that reason,they crack and give your fish a nice jolt every time it turns on. Don't think it would be fun if you had your hands in there doing maintenance and it went on if you had not noticed crack. I use Marineland stealth heaters....love em
All aqua one products are ****. Poor quality, big failure rate. but thats what you get for going mainstream LFS, avoid em at all cost. especially strickly aquariums, they know ****ing nothing.