1 system ac tune up complete. Did not change filter. Added chlorine tablets to evap coil drain pan to help keep drain line clean! Evap coil is rusty. Checked mechanical and electrical components of system, all operating within manufacturer specifications. Refrigerant levels are good. Chemically washed condenser coil and applied rust proof waxing. Recommended adding performance enhancement system to take a load off of the compressor and prolong the life of the system. Recommend apco air purification system to keep evap coil clean, prevent mold, and kill bacteria and viruses for overall better air quality. System is operating normal at this time.