I bought the same set up for Ca, Alk and Mag with the pumps. Works perfectly. I also bought the digital timers which also work perfectly. The nice thing about the digital timers; they are battery backed-up so if you have a power failure they keep on working.
I would get the larger containers for the mix. They offer the 2.5gal containers, buy them. Depending on the Ca draw of your tank, it will keep you from mixing up new solutions more often.