Bought an SWC 250 extreme. Questions

[hrdneglcry]

I bought this SWC 250 extreme. I did not know it was so huge and one of the pumps is broken I think. The pumps are SWC Sicce PSK 2500's. The one not running has a rust stain on the impeller. Can this be run with one pump with a higher gph than the one PSK 2500 or does it need two to run efficiently?

 

[blaxsun]

I'd replace the rusted pump with a new one and run the pair of pumps as designed.