Bad quality water from well in Calicut, Kerala - Need an economical purification method

I am living near calicut . My house construction is going on and it is at the final stage now. My problem is with the well water. The well was constructed 2 years back. since construction I am very much upset about the color of the water . It is slightly blackish in colour. some times the color turns out to be normal, depending upon certain weather condition . I can not conclude which weather makes it clearer. There is no bad smell or taste .I have done water analysis in a central govt laboratory in calicut and the result showed that the water is fit for drinking. The land area is about 35 cents and there is no septic tank in the near vicinity. The location is about 1km from the sea. The depth of well is about 4.5 meters.Recently I have consulted one traditional expert in this field and he has suggested to fill back the well about 50 cm with pure sand. Last year during summer the water was completely pumped out and the walls were cleaned. Surprisingly the water became crystal clear. But it lasted only for a couple of days and after wards it went back to same stage as before. To over come the problem I have purchased the near by plot whcih is about 30 Cents and I tried my luck by digging another well. Unfortunately it was worse than the exisiting well. The color is always green. I am unable to move into the new house which will be ready for occupation in few months for the above reasons. Now I have dug a bore well inside the well about 2 metes deaper the present deapth . The water from this bore well is far better than the well water.

I would appreciate if you can advise a solution to my problem ? will it find a good result if a I fill back 50 cm with sand? Is there any solution like filling charcoal in the well? If yes please advise the method. Is there any other alternate methods to change the colour of water ? Is it a recommended practise to cover the well top to prevent sunlight , so that water color will become normal? If no solution is possible kindly advise an economically feasibl purification method at the header level(overhead tank).

Expecting your valuable reply,

Abdul Razak.K