Im trying to save money on my weed killer. When I first started working for a landscaper I remember that he would mix up some special potion into his spray pump. I think he may have used some kind of acid. I did a google search and found a recipe for 1 teaspoon salt, 1 teaspoon dish soap, 1 gal. vinegar. Unfortunately alot of the houses I service have orange/red bricks and I dont want to bleach the color using the vinegar. Is there something I can mix myself to use as an alternative to round up weed killer?