Reef Crystal IO salt

[whatcaneyedo]

A cup full should get you to where you want to be.

I make about 27gal at a time to do a 10% water change on my system. I use half IO salt and half Seachem Reef salt then add a little more than 2 cups of a similar Mg mix. By doing so my tanks Ca is 450, Alk is 9dkh and Mg is 1450.

Or use this calculator http://home.comcast.net/~jdieck1/chemcalc.html

To raise 15gal of water from Mg 1000 to 1500 use 8.3oz (56.3 tsp aka 1 cup). If you dont want to go as high as 1500 try 3/4 cup.