Pool liner exploding

[davidbryn]

after two years of not using the pool I took the covers off to prepare it ready for use, I lowered the level of water to clean it out , their was water between the liner and the pool structure, so after cleaning it out I started to fill it slowly , and pumped the water from behind the liner. at this time the water level was about 28 inches , the vibration. from the pump caused the pipe to fall and take with it a brick that was keeping the pipe at the edge of the pool. their was a loud bang and the liner shredded , see photo. has anyone any idea why this happened , thanks for any answers, davidbryn.