Seriously though, if you are going to make the change, make it very gradual, I'd say no more than 10% at a time. There have been horror stories posted all over about bad things happening, we saw some ill effects within two water changes using IO instead of Oceanic, I wasn't watching Ca and Alk like I should have been that could have prevented it... instead just tossed the IO and found a new supplier for Oceanic.

BTW very happy looking sun coral