I've been using Baqucil, and for me it works, small pool etc... But, this year the pool has an organic problem and the sides of the pool have a rust colored film. This straight oxidixer is suppose to break this cycle, and allow the Baquacil to work again. I was sold 2 bags for $10. and was told to put it in the skimmer and come back in 2 days with new pool sample. The water itself is fine, only problem is with sides and bottom.