The first digit of the model number is the maximum gallons per minute the pump is able to accomplish. The last digit of the module number is the number of stages in the pump.
Make sure you oversize the array by at least 20% and 30% is better.
Grundfos pumps have a 30 to 300 DC or AC voltage window but try to stay in the middle of the voltage range. If you are using 12 volt modules, expect to use three or four modules in series.
