SDL Getting weird colors when drawing over surface : I'm trying to learn sdl by creating a quick and simple tile-based game. I've drawn my tiles on two layers. The first layer draws the water, lava, and most of the grass. But the problem is the second layer which as you can see with the image below for some reason tiles with water or cliff underneath have a reddish tent. I'm bliting every tile to a surface then bliting that surface to the main surface every frame.

Here's a link to an image of my problem:
http://i.imgur.com/LJgHyGb.jpg

I don't understand what's causing this. 