Wow, is that a sump or a rat maze? Very cool. As for the salt water making, I just go with the powerhead in a bucket. If you get one of those 30 something gallon Brute trashcans, you can make up a bunch of water all at once. Fill the trash can with RO/DI water, drop in a powerhead (Maxijet 1200s are fairly cheap and work just fine), and let the saltwater mix at least overnight. Cover the trash can, and the salt water should be good pretty much indefinitely.
To make it semi-automated, change out that Maxijet with a Mag pump. That way, when you're ready to add the new saltwater to the tank, you can just get a nice long length of flexible tubing from the hardware store and connect it to the Mag to pump the water to the tank.
The other ideas will of course save you a lot of time in the long run, but that's my suggestion if you don't want to invest the time in the initial setup.
