Super-Chlorination is adding enough free chlorine to reduce the Combined Chlorine to Zero.

Paying special attention to Combined Chlorine levels can reduce or eliminate having to periodically Chlorine Shock your pool.  The advantage is lower chlorine consumption and increased swimming time.

A healthy pool should have NO Combined Chlorine! Combined Chlorine is "used up" Chlorine that has "Combined" with swimmer waste and other debris.

Combined Chlorine is Chlorine which no longer has any sanitizing capability.
Combined Chlorine gives off a strong offensive Chlorine smell even though Total Chlorine levels are relatively low. This usually indicates that the pool needs to be super chlorinated with large quantities of Free Chlorine.

If there is no strong Chlorine smell and the water has a crystal clear appearance, you can probably just add enough additional Chlorine to achieve "Breakpoint Chlorination" or "super chlorination".

Super-Chlorination requires that you add enough additional Chlorine to equal 10 times the amount of Combined Chlorine.

Example: If Combined Chlorine is 0.5 PPM you would add 5 PPM of Free Chlorine.