I have a dedicated 20 amp circuit then my tank is protected by a GFCI outlet.
I have the majority of my tank on a 20 amp gfci setup. I run my return pump on a traditional outlet cause I don't want a "false" current tripping it and cutting off the tanks lifeline.
I have the main pump on it's own GFCI protected circuit. If it trips, the power heads and all the other equipment keep on running. The lights are also on their own circuit and they have tripped the GFCI more than once. So in all I have 3 20 amp GFCI circuits.
Mine has the heater in the sump so while I'll keep current in the tank due to a host of other measures, I don't have a heater in the DT so I need the return to continue to deliver water from the sump