eli5: Why is water clear in small amount but blue in large amount like an ocean?

Question

I thought it might be the reflection from the sky but if that was the case, why does the ocean appears more blue the deeper you go?

In: 2918

Answer 1

What is in the water is what makes it that color.

Northern California oceans look green to me. Lots of nutrients. Algae. Zoo plankton.

Clear tropical water has almost no nutrients..