The Tower Tank is illuminated with up to six overhead lamps. The lamps are divided into three banks of two with each bank on a separate timer.

The lamps consist of four 1000-watt phosphor-coated metal halide lamps (divided into two banks each with a timer), plus two 400-watt mercury vapour lamps (both connected to the same timer).

Light intensity is in the order of 10-40% of the normal midday summer sun, with measured light levels between 0.04-0.16 cal/cm2/min from the edge to the centre of the tank.