Backyard Aquaponics
A place to discuss aquaponics

why? what's the difference?

Brushless motors have no contact brushes that wear. Brushed motors have brushes that actually rub inside the motor and they wear out.

Brushless motors are also more efficient/powerful... from Wiki..

BLDC motors offer several advantages over brushed DC motors, including more torque per weight, more torque per watt (increased efficiency), increased reliability, reduced noise, longer lifetime (no brush and commutator erosion), elimination of ionizing sparks from the commutator, and overall reduction of electromagnetic interference (EMI). With no windings on the rotor, they are not subjected to centrifugal forces, and because the windings are supported by the housing, they can be cooled by conduction, requiring no airflow inside the motor for cooling. This in turn means that the motor's internals can be entirely enclosed and protected from dirt or other foreign matter.