To raise Ca and Alk together try a little Kalk, use the calculator to figure out how much to add to your top off water.
http://home.comcast.net/~jdieck1/chemcalc.html
Enter your present Ca and Alk readings, enter your target and select the product you want to use. I did it, I wanted to raise my Ca and Alk, to use ESV I would have had to use half the bottle of each. The target I wanted indicated I should add 5 litres of saturated limewater for the Ca and 2 liters for the Alk. I added the 2 and then a bit of the ESV a couple days later and Alk and Ca are great. Ca is 425 and Alk is 9dKH
Douglas