CB1 - All sorts of factors affect how fast a body of water will warm. Darker water may or may not warm faster depending. Rate of warming of stained waters is affected by the type of stain and how the light rays peneterate through the water. Darker water from tannins warms rapidly and usually causes a more shallow epilimnion due to most of the light getting absorbed relatively quickly and not penetrating very deep. Concentration of the stain also has an impact.

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