I believe you are talking about Aqua Fortis, which is Nitric Acid with Iron disolved in to make a solution of Ferric Nitrate.
The simple answer is yes you can use multiple times to get the desired color you want, with heating between coats to get it to activate, and create that reddish brown color. I use Ferric Cloride crystals diluted in water to make mine (read less fumes/danger) You could just get Wakhon Bay A/F from Mike Lea, or Log Cabin sells it also. It comes with directions. You definately want to make some tests on scraps or inside the barrel channel first, as colors will vary from stock to stock, even with the same type of wood. You will get from a nice light brown to a deep reddish brown, and every shade in between, by varying your application and the wood type.
Bill