Nice pics Kris!  The white setting is white balance.  I do this post processing in either Adobe Lightroom or Coral Photopaint.  Most people use Photoshop but I have been using Photopaint for years now.  If you dont have any of those programs I would think Gimp can do it also.  There also might be a setting in your camera, if so you can try cards (never worked for me) or take a piece of styrofoam, stick it in your tank and WB with your camera.