Trimec is a great Charlie eradicator and is friendly on the grass. Apply it while charlie is on the prowl, then re-apply 4 weeks later. Nothing better than to see Charlie get red, then die.
On adding dish soap, when filling a pump sprayer use 2 tablespoons per gallon, but mix the soap in warm water separately in a glass and add to the chemical water mix in the tank. I don’t fill the tank off a hose or a faucet either. I add the chemical then fill by pouring water in the tank from a pail. When the water/soap and chemical are in I screw in the pump and give the whole works a shake….way less of the chemical laden foam outside of the tank this way.