That explains the corrosion, still think its cavitation that's causing all the issues.

Link that shows cavitation in pool pump

https://www.youtube.com/watch?v=cvAa07osJoA&ab_channel=ChlorineKingPoolService

Link talks about not using copper pipe in pool systems

https://www.commercial-industrial-supply.com/resource-center/types-piping-used-swimming-pool-installation/#:~:text=Copper%20-%20Copper%20piping%20is%20no%20longer%20recommended,were%20installed%20before%20PVC%20pipe%20began%20being%20used.

Last edited by kk alaska; 03/31/21.
kk alaska

Alaska 7 months of winter then 5 months of tourists