When do you need to shock your pool??

[peachfuzz]

Edited--
Never mind.

[peachfuzz]

I don't think I bought the correct chemical. What I have is Shock Plus by Aqua Chem.
Ingredients are:
sodium dichloro-s-triazinertrione, 58.2%
Other ingredients, 41.8%

That isn't the right thing, is it...?

There wasn't a lot of pool chemicals left, and I was thinking this was the right one.