Seaflo 42 series pump with Venturi oxygenator

[@viperblck1]

I want to buy seaflo pump, but I want to choose the right series for my purpose, that is irrigation in my field with a 5 meter difference in heght from water tank to field.
Series 42 have intermittent duty cycle while other series have continous duty cycle. What is the difference between intermittent and continuos duty cycle ?

[@aurelijusbickaitis2899]

Very short-lived, only 2 years old. The manufacturer does not accept warranty service. Membranes hardened, water leaked, bearings rusted.