Beautiful edit from the original post!

You're well on your way to defeating the ever-looming Grid!
You got rid of the repitition explained before, but now look at your image of the tiled "ocean"

Now, zoom it once, so you can see it better.
See how there seem to be horizontal "lines" in the image? They're everywhere, honestly, but the most obvious one is made from the top five rows of pixels in the tile itself. edit those lines out, then the Grid is almost invisible.