RR1-2.5 Rid O' Rust Rust Stain Preventer 2x Well Water Stain Preventer Concentrate REPLACES FORMULA 500 & 2000 Prevents rust and lime scale staining caused by well-based irrigation Case of 2- 2.5 gallon bottles 2- 2.5 gallon bottles of RR1 are equal to 1- 5 bucket of Formula 500 1- 2.5 gallon bottle of RR1 is equal to 1- 5 gallon bucket of Formula 2000