I've used a dosing pump plugged into an ordinary appliance timer with it's 10-15 minute increments. I set it to turn on for a few minutes/day to deliver the amount of fluid needed. 

Something to think about is the strength of the solution to be dosed. I make my own Alk and Ca solutions, so they can be made as concentrated or as weak as needed. They are not as concentrated as the expensive pre-made solutions, but cost a lot less. Even the concentrated store bought solutions can be diluted with RO water. Of course as the stony coral, Coralline Algae and snail/invert population increases, the tanks need for Alk and Ca increases so the solution can be concentrated or the dosing time can be lengthened accordingly.