With a head height of 18" the sump was flooding the first sump compartment. I drilled three one inch holes to let water out in the second compartment. The water was moving so fast in the, .. ... ..1 1/4" pipe that almost no water was escaping out of the holes.
I put a 1 1/4" ball valve to apply a little back pressure.
3000 GPH! 6 foot headheight should bring it down to just over 2000.