I meant to add two things. I have worked out a trade with a guy for a new RO/DI unit. This will allow me to put the unit upstairs, as it has a booster pump with it. It's a Vertex Puratek 100 GPD unit. This is good news... as long as the trade goes through as planned.
I also found out why it is important to have dual float switches for the ATO. Last night, I noticed that my sump level was about 3/4" higher than normal. I looked, and my primary switch has failed. I suppose that's my fault, as it's been running for almost 3 months now without cleaning... but a good reminder that redundancy in an aquarium like this is very very very important.