Rid O' Rust

[Fishin LCO]

Help..... We have horrible rust stains from our irrigation systems around here and I told a customer I would remove the rust for him. My problem is I am trying to find a cheaper supplier of Rid O' Rust. If anyone knows of a good supplier I would be greatly appreciative.
Thanks
CC

 

[amar]

John Deere Landscapers has it. I think I saw it at Home Depot.

 

[metro-hp_48]

Is that anything like Gempler's Rust Converter?