Free chlorine

[meade]

Combined chlorine has little sanitizing ability, and no oxidizing ability. Therefore, if the total chlorine level is higher than free chlorine, that indicates the presence of combined chlorine. In that case you need to shock or superchlorinate your pool.

If my test kit only checks TC, will I see a change in the pool if CC it higher than FC that will trigger me to superchlorinate it?

[Simmons99]

Although a good test kit is the better choice. CC can leave a chlorine odor. If the pool is cloudy that will also let you know to shock the pool.

[Rangeball]

No, your test kit won't.

To specifically test for free chlorine, you need to get a different drop based kit that specifies it specifically tests for FC.