IO adjusting?


New member
Hi Randy,

I notice you use IO. When you mix it up for water changes, do you add calcium and/or magnesium when you make the water. Just wondering which way is easier. Adding after its added to the tank or in the mix itself.



Randy Holmes-Farley

Reef Chemist
Premium Member
I add a fixed amount to the new salt water before doing water changes. I don't measure it before or after the addition. I just assume it is roughly right based on typical levels and known addition amounts. The magnesium may get boosted above NSW values, but that is OK as it offsets loses due to calcification.