Water Tanks

Todays weather has been awful, the winds have not died down, but fortunately seem to have blown most of the dust away. We didn't go out at all (today is weekend for us) so this pic is taken from our apartment.
It gets really hot in summer - over 35 degrees C even at night and high in the 40's during the day and so the water in the tanks on the roofs gets HOT. So what do we do about that? We turn off the heaters on our geysers (hot water tanks) - the indoor geysers become cold water tanks and the tanks on the roof supply the hot water. How cool is that!!