I have 3 of the ECP-50m gyres barely used in boxes. I switched back to MLW/ELW pumps because the little single-sided gyres were ridiculously loud. I've been running MLW/ELW pumps on various tanks (and in my saltwater mixing bin) for years and have only ever gotten a stopped error once after sitting in my mixing bin (dry) for a week.
As for the Nero 3, the MINIMUM flowrate (1% in the app, but really 30% of the pump's capacity) is 600gph. I suggested the ELW-3m specifically because the MAXIMUM flow is 660gph, and it adjusts down from there.
But, as with everything else in this hobby, YMMV and all that.