You're right Scott, I never really noticed that halo effect. I guess I chalked up the colour change to shallower water.
I note that Phyllis's image doesn't have this halo. Phyllis can you recommend a digital haze filter?
It's pretty remarkable how much a photo can be improved. The original was shot through a helicopter cockpit window (thus the flatness and I think the haze) with the helicopter tilting upwards. Got a bunch of these shots - tried working with the best one. One thing I've learned - carry extra memory cards! Downgrading from super high quality to high quality will affect any prints bigger than 8x10.