Never a good idea to have glass anything around the pool, even an above ground pool. A glass container is less like to be knocked into an AGP and break, however it is more likely to break if knocked to the ground from 4 feet high. Not too many people wear shoes to the pool, so the risk of injury is high if glass breaks on the ground. If it breaks in the pool it can cause injury, damage liners, and potentially damage the pump. If broken glass does successfully navigate the pump and filter, you still have to deal with it when you clean the filter. Clear glass has the extra bonus of being next to impossible to see underwater.