The clarity of the water is due to the depth from which it is drawn. There is no organic activity down there and no "spare" oxigen. Just to put your mind at rest, the metals which get attacked most voraciously are the soft metals like copper, aluminium and, of course, brass. I did my own solar hot water heat exchanger which works brilliantly but, being made from copper, soon developed some pinhole leaks and as for the electric immersion heater, I'll Say no more. all is well now. Soft water is king. Your deep well pump should be entirely stainless steel. the shaft and electrical connections will be segregated from the water by some extremely strong neoprene rubber gaskets so there should be no problem for the pump.
