If you have the return pump in a sump underneath the aquarium, then the flow rate should be fine. As pumps push water up, the amount of water slows down, so if the pump pushes water up 3 feet to get it back into the tank, the amount of water going back into the tank should be less than that stated on the pump.
Check the pump packaging and see if it has a chart showing water pumped at certain heights.
If the pump does pump too much water you can put a T-piece and tap on the return line and bleed a small amount of water off so it goes back into the sump, and less water will be pumped up to the tank.
