okay so i came home today to notice the overflow was cracking, its the back left corner of the tank (300gal, 8ft long) tank had been up for close to 2 years, the support on top the overflow cracked, and the back left corner has started to crack its just below the waterline in the overflow a very very small leak, the only thing i can notice is the foam board is very compressed only in the back corner where the crack is, it looks like to me that the back corner just sank, tank is level and im not sure at this point what i should do?