We have a number of Apex controllers on various service tanks. All of them were set up by clients and whenever they have issues it's always such a hassle to do any programming over the net.
I'm also of the opinion that the more you want to control an already controlled device, the more headaches will result.
I really like the simplicity of the older AC3's and am actually in the process of retrofitting some of these tanks with old skool controllers.
Easy to figure out without a book or a computer.