iPad

I use the Apex to turn various pieces of gear on and off, to get alerts when certain items are out of range, and to track water parameters. 

For the last decade, I've been using Neptune System's Aquacontroller.  First I had the AC II, then later upgraded to the AC 3.  Near the end of 2011, I gifted myself the Apex controller, the latest available version at that time.  The Apex has been around for a couple of years, and many of my friends swear by it.