I use something similar. I have the Aquatronica dosing module for my Aquatronica controller. It's awesome. I just tell it how many ml of each supplment to add and it figure out how to spread it out during the day. You can program it for specific times too, and time spans of course. I highly recommend dosing this way. You could also use the BRS Drew's Doser and the BRS Doser. One is really slow, like 1.3ml per minute, so you can really have a lot of control with them.
I actually have 2 Aquatronica dosing pumps now. I put Alk, Ca & Mg on one and I use the Tropic Marin Pro Coral K+ on one and A- on another (only 5ml of each daily). This gives me one extra channel for a spare, should one of them break.
I also love these dosers because when I mix fresh saltwater, I know that I need to dose 20ml of Alk and 10ml of Mg and I can tell it to do that one time when i do the water change.
IMO, a great doser is money well spent. They are very reliable too.