Models of lakes are used to provide insights into water quality at some future point in time, so that management actions may be targeted and cost-effective. In the past, small-scale physical models were used to simulate lake environments (Figure 1), but nowadays computer models are used to test potential management options. Computer models use a series of mathematical equations to describe the complex interactions amongst physical, chemical and biological processes that affect the water quality of a lake. The equations are stitched together consecutively in a computer program, allowing millions of calculations to take place in a single simulation.