Calcium question

[degbowl]

I've had a sw tank for 2 years now. I use RO water and Oceanic salt. My Calcium is at 450. I helped a friend setup a tank 6 months ago. He is also using RO water and Oceanic salt. His calcium is at 800. Is that possible. I asked him for a water sample so I can test it. His tank is FOWLR but he eventually wants corals. Does he need to lower his calcium and how can he lower it? Thanks in advance for any help.
Jim

 

[worldwide zoo]

I'd test again with a different kit fo sure. If it stays above 600 for more than a week the corals will start to RTN at the tips. Some will say to just keep dosing alk till it balances out, however I'd do a series of water changes ASAP to correct it.