What she said . . .

But, let me emphasize the importance of getting a reliable CYA testkit . . . and 'guess-strips' don't count. They are never very accurate, and the CYA block is the least sensitive of them all.

Having high chlorine and high CYA now, under a cover is not a bad thing. And, it's not necessarily a bad thing once you open, BUT you must compensate. If your CYA is high, you MUST run high chlorine or you WILL have problems. The "Best Guess" page explains (in our signature blocks), and tells you what to do. But the starting place as a reasonably accurate CYA measurement.