Hello

I have a 9000 litres capacity concrete drinking water tank to store metro drinking water in the ground floor . As every one knows there was flood due to heavy unprecedented rain in Chennai city Tamil Nadu, India.  Hence there is a strong possibility of seepage of contaminated water in to the water tank. As soon as the contaminated water receded,  in order to purify the drinking water, I mixed 500 grams of bleaching powder in the water tank when the tank had its full water level. The water has since then been used and exhausted for all the purposes, including drinking and cooking. Is the ratio of mixing bleaching powder correct or excess. If in excess,  what is the side effect and what remedy do I have work on to rectify it. This had happened two days ago, and I need your help for this.

Thanks

A.M.Nainar Mohamed