It's very simple to fix the green color underwater problem:
1. Uninstall the ENB mods. ENB doesn't work properly with 1.5 (and ENB in general is really rather idiosyncratic

)
2. Delete skyrim.ini and skyrimprefs.ini, so that the game will regenerate them on launch.
3. Uninstall mods like Realistic Water Textures and use the latest version of the WATER mod which supports the 1.5 water.
4. Some people are still forcing steam on offline mode and stuck with patch 1.5.24. Patch 1.5.26 incorporates some fixes related to the underwater effects.
4. If all else fails, verify your steam cache.
Now if the problem
doesn't get fixed after all this, there's something seriously wrong with your copy of Skyrim
