the original water should accompany the specimens or aged of aquarium water may be substituted. water may be boiled to destroy other organism prior to dispensing. Tap water should not be use as it frequently is contaminated by chlorine or various metals which prove toxin to the algae. Specimens should not be overcrowded and the ratio of surface area to water volume should be favorable for complete aeration. Direct sunlight should be avoided in most cases. light from a north window proves quite adequate during the growing season , although artificial lighting will enhance algal growth .