Problem: Muriatic Acid stain on Concrete pool deck

I came across a product called Concrete Rust Remover (via a Google advertisement, Ben may be interested to know, displayed on this very page). The MSDS states that it contains sodium hydrosulfite.

Does anyone know if sodium hydrosulfite would be effective (or harmful) in removing the muriatic acid stains laid down more than 2 years ago on my concrete deck? The company's website claims that it can be used to eliminate the orange stains caused by car battery acid.

Product - http://www.theruststore.com/Concrete-Rust-Removers-C29.aspx
Claim - http://www.theruststore.com/Battery-Acid-Stains-on-Concrete-W57C36.aspx
MSDS - http://www.theruststore.com/msds/rust-remover-for-concrete.doc