While I work on wells I am no expert. I have a friend that has, I would guess hydrogen sulphide in the well causing the rotton egg smell. I want to chlorine the well for him but I am not sure of how mich to use and if it will/can harm the pump. It is a submergable, the well is 90' and he is getting back to me as to the water depth in it. My question is, is there a formula as to the amount of chlorine to use based on the amount of water in the well? I know how to do it just not how much to use or how long to leave it in the well B4 flushing it out.