Phosphate remover does not kill algae directly but takes away their food source. Algae utilizes phosphate and nitrate produced by your fish and their environment to grow and flourish. If you remove these with your regular maintenance, minimize food waste and add a phosphate binder. Most phosphate binders can be used temporarily to take care of spikes until you get back to your normal routine. In the rare case your source water is high in phosphates, you may need to use a phosphate-binder long term with severe algae issues.