Help with pressure washing and bleaching?

The streaks are caused by holding the nozzle to close to the the concrete, raise the nozzle so it doesn't streak. About 15 percent bleach 85 percent water (about 9 1/2 oz.bleach per gallon of water) will kill most fungus and remove other stains. Oil stains may require a Degreaser as the concrete is porous and will absorb the the oil or grease.