What causes graying or yellowing of clothes during washing?

Not enough detergent, hard water, water that is not hot enough, overloading, or detergent not dissolving properly can cause graying or yellowing. Use more detergent (especially with larger loads), use a water conditioner like Calgon or install a water softener, ensure your water heater is delivering water at 120°F–140°F (48°C–60°C), and select load size to match your clothes load.