The effect of temperature on the rate of diffusion of KMnO4 into water.?

I had an experiment on the effect of the temperature on the rate of diffusion of KMnO4 into water in cl. We examined the rate of diffusion at various temperatures of 0,24,37, and 53C over 60min. We were expecting that KMnO4 diffuse faster at higher temperature because molecules move faster at higher temperature. However, our result shows not much difference in the rate of diffusion and the temperature does not affect the rate of diffusion. Do you think this happened because of the huge error in our experiment or our hypothesis was wrong?