I don't know if this is normal or not but i have this 200gal reefs tank that have been set up like about 3-4 months ago and the magnesium level are now too low. I'm using a calcium reactor for that tank the calcium level are still droping no many how i adjust the reactor. and i have add calcium chloride but it wouldn't raise a bit and currently at 360ppm. I'm adding magnesium by 25ppm daily now.. today is the first day but it's rather expensive over here. what chemical could i use to add calcium?