This paper reviews the development of the SCUM series of models and pr
esents additional algorithms for calculating surface radiation flux an
d growth. The first SCUM models used data obtained by laboratory inves
tigation of Oscillatoria agardhii by Kromkamp & Walsby (1990). However
when applied to other species the models became unstable. More recent
attempts have taken a different and more theoretical approach combini
ng lake mixing and modelling components of SCUM with a buoyancy routin
e (CYANARA) developed at the Institute of Freshwater Ecology. Model al
gorithms and sample model results are briefly described. The growing i
mportance of the World Wide Web in modelling is highlighted and explai
ned.