What a numpty!

All depends on the relative external temperature. A black surface will radiate heat more efficiently than a white one; not so certain what happens when the container is clear - I guess that's dependent on the other characteristics of the material.

They certainly *could* be a reason why he's right.

Does it really matter? if its a tank for general purpose water and not for human consumption as he has stated then the colour is irrelevent.

As to the colour of something that keeps cool... Manufactureres changed heatsinks from silver(aluminium) to black because it dissapated heat better.

HTH

.. >This chap recons his black water tank will keep the water cooler than a .. >clear one! .. >

.. >

.. >Steve .. >

But being black it will lessen or even stop algae growing inside, from my first hand experience from useing both.

Mike P