I have been running a Genesis water change system for almost 2 years and it works flawlessly. It has dual float switches checking to make sure I have premixed salt and my sump level is ok before it activates. I change 1 gallon of water every 4 hours. It could not have been simpler to install and easy as pie to setup and run. It will run you about $4 or 500 though.
One caveat, your ATO. Genesis sells an ATO too, but I thought it was a waste of money since I have an apex. So what I do is I have my ATO come on every 4 hours but on a 2 hour different cycle than the Genesis so they don't run at the same time. Example, WC at 4,8,12 etc and ATO runs at 2,6,10 etc.
If you go the diy route, that's the one thing you have to figure out is how to turn off your ATO while your doing the water change.
Add in a skimmer neck cleaner with a 1 gallon over flow collection chamber and my weekly maintenance is almost nothing. I mix a 60 gal drum of salt, empty my skimmer overflow and I'm done. I have to clean the neck and head monthly.