terraria
In the 1.2 update, I've noticed that water will occasionally change color (this has been most notable for me in a few underground water pools). For example, one pool of water will occasionally turn from blue to orange and back again.
What, if anything, is controlling the water color changes? Is it biome specific (i.e. I'm moving between two different biomes and I don't realize it)?
That, my friend, is how you create obsidian.
You can find a very useful guide on farming obsidian here.
The liquid physics in Terraria are not completely precise. You can abuse it to duplicate them. Good thing, too, since transporting a decent amount of lava/water anywhere is a huge pain.
Applying #2 and #3, this is a very simple liquid duping setup:
The lava is placed on the edge, where it flows into both the container and the 1-block "basin" on the right side. Both "portions" are enough to be picked up by a bucket again (though in this case, the first scoop will be spread too thinly in the container).
Best Answer
When you see water changing colors, you are moving into a new biome. For example, if you see a pool of water right between a Snow and Desert biome, you will see the water change from icey blue to muddy orange. When you're underground, you could also be transitioning between layers. This will be accompanied by a change in backgrounds.
Aside from that, water now turns red during a blood moon.