how to choose submersible water well pump？

Submersible water well pump how to choose and precautions are as follows:
      1, according to the well of the water, select the flow of the submersible water well pump.
      2, well water sediment more than one ten thousandth of the well, should not be installed using deep well pump. Well water sediment concentration is too large, if more than 0.1%, will accelerate the wear of rubber bearings, causing the pump vibration, shorten the pump life.
      3, according to the well diameter, water quality initial pump type. Different types of pumps on the size of the wellbore diameter have certain requirements, the maximum size of the pump to be smaller than the diameter of 25 ~ 50mm. The pump part can not close the well wall to prevent the pump vibration will damage the well.
      4, according to the depth of the well water level and water pipe head loss, to determine the actual needs of the well pump head, that is, the pump head. Loss of the head is usually a net head of 6 to 9%, usually 1 ~ 2m. Water pump the bottom of a impeller into the water depth to 1 ~ 1.5m is appropriate.