White residue floating on pool surface

Hello, I have been trying to clear my pool for several weeks now. It has been cloudy and I had the water tested. Thursday we cleaned the cartridges and I was told Saturday that I had no clorine and to clean my salt cell. I also was told to put 2 bags of nonchlorine shock in and run 4hours, then 1quart of Acid every 4 hours until I used 2 gallons. Now, there's this white foamy residue floating on the pool. We cleaned the cell yesterday. I'm also supposed to add metal free at the end because of cooper in the water. The white film appeared last night. What is going on?