I had a water softener installed about 2 years ago. I believe it was a standard "internet" flecks unit. It stands about 5 ft tall and has been working flawlessly for the last 2 years. My system is a in ground well pump set at 35lbs. This flows to the house and goes through a large "whole house filter" to remove any sand. It then goes through a sulfur remover (looks like water softener) and then the water softener and then a booster pump bringing the 35lbs of pressure up to 95lbs to feed up a 3 story house. This has worked quite well until today. I am in florida and the temp went down below freezing last night some of the well head piping is exposed outside. My shower ended about 10 min in to it when the water pressure dropped to almost nothing. I when to the garage where the tanks are and noticed a cracking noise. To my horror , I suddenly realized the water softener resin tank was bulging and the fibers were cracking and splitting as if it was being blown up. I ran to the breaker box and killed all power to house and pumps. After a short time i checked the pressure meters that are before and after the booster and both showed zero. so I bypassed the water softener and then powered everything up keeping an eye on the pressures. All looks good and is working fine les the water softener. What the hell happened to the water softener tank? Nothing else looks compromised and no leaks.