Any ideas on getting rid of white outlines of dried puddles on tennis courts AFTER they were cleaned?

Question

After cleaning the courts with a water broom on a very hot day the edges of where the water ran off the courts had dried and left whitish marks around the edges. These were downslope from the cleaning and had already formed by the time I got to that part of the court to clean. I'm thinking it's minerals in the water as I cleaned each row with three passes to insure all the dirt was removed. Anyone know of a chemical or trick to get rid of these stains?

Answer 1

i've seen these things too, but did not do anything. the stains will disappear in 1 or days. we do not use chemicals or special cleaning materials.