This looks like bad seawater.
Is it aireated? Any biological control, or is this for intake?
How long do you expect the pump to last?
Any chance of sand/silt in the intake? How good is hte protection structure?
What options is the pump mfg offering you?
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.