Why would Nolan use CGI for basically a pool filled with some sort of liquid, instead of just pouring some coloured water in it?
Isn't that a little bit unpractical from a financial point of view?
Enhancing real water with CGI is one thing, but creating it completely on the computer would be a little bit decadent, don't you think? (Though of course, I'm no CGI expert.)
I think Nuffsaid's explanation is much more likely.
A pit - yes. But in the terms of a deep hole, tunnel, entrance to a cave/prison, call it whatever you want.
But the lazarus pit? Don't see it happening...