The difference between Trichlor and dichlor is that dichlor has around 55-62 % available chlorine content and is not as harsh on your skin. On the other hand, Trichlor is more expensive and potent because it contains 90% concentration. Additionally, Trichlor will often produce a slight decrease in the pH and total alkalinity of your pool, but Dichlor would not since it has a more neutral pH balance.