Does this check valve look ok or does it need to be replaced ?
I have a waterfall basin that sits below my pool that is connected to an autofill to refill my pool via a waterfall pump. Sometimes when the waterfall basin is low (lots of splash out etc so water is being put back into the pool) I notice in those cases that my pool water gets lowered if the waterfall pump is turned off and I was wondering if it’s back flowing to the waterfall basin since the basin sits lower. The check valve in the pics is last check valve back to the pool from the water basin pump (the circled part). Does this check valve look like it needs to be replaced? Also do I need to replace the other check valves around the waterfall pump? Given this is the last check valve from the waterfall pump before it goes in the pool I imagine if that’s working and preventing backflow then there shouldn’t be any backflow back to the basin or are the others responsible for that also ? Thanks for your help!