Wow how paranoid I can get with this marine tank...
Here's mine:
1. Water spilling on the hardwood floor when moving my tank stand a few centimeters. This causes water to end up underneath the stand. Oh how the mind makes you crazy forcing you to worry about how messed up the hardwood floor would be underneath that stand.
2. One day the glass will crack and all that water, wow!
3.. Plumbing begining to leak
I dont know if it's just me but this hobby has got me insane!