So, Drinking Night Vision and water breathing and then diving into water will result in invisible water.
There is supposed to be blue fog in distance, like it was in 1.7.
What happend was that when having night vision effect and water breathing effect at the same time while being in water will have the water invisible.
How to:
1. Play minecraft on 14w25a/b.
2. Drink a Potion of Night Vision and a Potion of Water Breathing.
3. Dive into Water.
Normal