I'm EXTREMELY skeptical of your judgment. The light level of the water in Drowned Downtown Zone is 160, and that level is supposed to be darker than the sort of level you're trying to make here.Changed the water's light level to 144. Any higher and it wouldn't look right unless using Opengl. At least in my eyes.
Could you do me a favor? Show me two screenshots: one with the light level at 144 and one with the light level at 192. Then I'll tell you if I agree with your statement that 144 is the maximum level that would look right.