Do I need to neutralize iron nitrate stain after applying it?
Jim does not neutralize the iron nitrate he uses and has not seen a darkening problem over time, as long as it is kept out of the inlets and the product is heated well during use, which drives off residual acid. Some experienced builders do prefer to neutralize with a baking soda and water solution, and either approach can work, but this only applies to the product Kibler's makes and sells.