Thanks for all of the feedback so far.

I think I'll go with keeping it simple to start out with and just use tap and switch to RO if the need arises.
John, I'm actually avoiding a coral cat as they reportedly bite at the fish more. There are at least three species of Bamboo's that stay on the smaller end that I'm currently keeping an eye out for:
Chiloscyllium griseum = 29" max (located a source online but have LFS looking also)
Chiloscyllium arabicum = 27" max (avg 20-24")
Chiloscyllium hasseltii = 24" max
I definately could not bring myself to get one of the commonly available C. punctatum or C. plagiosum for this tank. A few have tried to talk me into it saying it'd be fine for years but I'd like whatever I get to be fine for life.