You should get the ph lower before you shock, that I do know. As for a saltwater pool, I'm not sure how that affects the cl level itself, but you need to find out your CYA (cyanuric acid) level because you might need way more cl than just 5 or 6. You can take the cl level up to 20 and beyond (depending on your CYA level), and that is what kills the algae. I can't imagine silver in any form doing this.