Mini Micro Submersible Water Pump

You might be searching for a pump that operates on 3-6 V and gives an output of above 70 L/H  then this could be the best choice for your project.

This DC 3-6 V Mini Micro Submersible Water Pump is a low-cost, small-size Submersible Pump Motor that can be operated from a 2.5 ~ 6V power supply. It can take up to 120 liters per hour with a very low current consumption of 220mA. Just connect the tube pipe to the motor outlet, submerge it in water, and power it.