That is scary, & we do learn from our mistakes.
Last week I drained half my pool cuz the CYA level was too high from previous owners years of Trichlor tabs that leave traces of the stuff w/ every tablet. Then at 2 in the morn. I was reading threads on forums that talk about how peeps have had their pools pop litteraly outa the ground with all the displacement from unknown groundwater levels. I couldnt sleep all night w/ the thought of not having done enough research, dumping 10K glns, & taking A chance on a killed summer & a 50-75K bill to correct if it did happen. All was good in the morning, & while not as bad as a car falling on your head, sometimes you risk those failed results for not seeing the whole picture or cutting safety corners of a job before you take it on.
Anyway, the rewards were good in the end