One or Two closed loop pumps
 

Turns out that my closed loop pump isn't enough flow for the tank so I either buy a new larger pump or a new pump the same size and use it with my existing with some reconfiguring of the plumbing. I want about 1400GPH and have a single 1" bulkhead to feed the closed loop.

Would using two 700gph pumps off the same 1" input cause them to cavitate each other?

Thanks,
Ken

I'd recommend a single high pressure pump (because of the 1" bulkhead) or get your tank drilled again for the second pump.