Brushing your pool will keep dirt from occupying the small pores and starting small organic farms. Steel bristled brushes, called algae brushes, are very effective. Remember to never use a steel brush on a vinyl lined pool. Done regularly, brushing can also reduce the time spent vacuuming. Brush from the shallow end towards the deep end in overlapping strokes. Circle the pool towards the main drain, and much of the dirt will be swept up into the filter in this manner.