I finally had a chance to install my ATO. I lose an average 1200 mL of water a day due to evaporation. I am using a 5 gallon bucket to hold 2 weeks worth of RO/DI (another awesome tip from ajn81). The top off/dosing pump is a BRS 50 mL/min pump. Its pretty nice. My Apex is controlling the top off by turning the pump on every 15 minutes for 15 seconds. For those who care, the code looks like:
  • OSC 000:00/000:15/014:45

Here is a pic of my little setup: