Instant ocean, new bucket over 600ppm?

[Enigma]

My Hanna Calcium checker is fussy. I'm having a hard time with it. It routinely tests high. Not as high as what the values you're getting, but high. My ELOS and Seachem calcium tests agree with each other, while my checker is often 50ppm higher for some reason.

I would test again with the checker, and if the values are still high, have your LFS or another reefer check the values for you (or, purchase a reliable titration test).