Measure out the rice chex, pretzels and crackers and place them in a large bowl together. (If using my homemade crackers {link is above in the ingredients}, add them after you toss the cereal and pretzels because the butter makes them very soggy and cardboard-like. They will still get the ranch flavor without the butter on them.) Melt the butter and pour over the snack mix. Using a rubber spatula or spoon, fold the mix very well to make sure every piece is evenly coated with butter. Sprinkle ranch dressing mix very slowly (start with half of the pack and then add more if you want more flavor) and fold again to make sure every piece is coated with the ranch powder. Taste your mix and see if you would like to add more ranch, if so, go ahead and add more until it is to your desired taste.