DevonDiver
N/A
What I suggested is not a piece of software, it's an 'action' that is downloadable from Adobe's website that can then be added to the Actions palette in Photoshop. I had a look at DevonDiver's link and at a quick glance, the steps in it are similar to what the underwater action does... but far quicker as it's 'automated.'
I used to use the Underwater Action, but I found that it wasn't flexible enough to provide good results on the majority of photos, especially when there was a lack of original red pixel information.
You can get simularly good 1-step results simply by using the eyedrop sampler in Curves to designate black and white points in the photo. But if the red pixels aren't there, it will still look quite washed out, or can be color skewed.
Using the Channel Mixer is the only way to add the red pixel information, if it wasn't captured when you originally took the pic. That step cannot be automated well, because it is very individual to the photo.