My CYA level was zero or very close, so added the recommended amount on the packaging. How soon after adding can i add additional chlorine or shock? I've been battling algae and my chlorine levels are almost non-existent, hence the CYA. The algae appears to be gone, pool is still a bit cloudly, but can see the bottom. I'm thinking I need to add chlorine ASAP so the algae doesn't have a chance.