Sunlight pierce trough water & lit up instead of dark-ish (idk what to put sorry..)

[ghost]

The suns light pierce trough water ended up having sunlight in my underwater tunnel instead of dark-ish (edit)

[javiergcim]

Sorry, but you don't give me enough information to interpret the images and the problem.

Why is one image bright and the other dark? What changes between them, and how do you think it should look?