If this is not available use boiled water from a spring, pond, lake, or river. A neutral pH of approximately 7 is desirable. The water must be free of metals such as copper and zinc. Chlorinated municipal water can be used for culturing with limited success. This water must be collected and aerated for at least 1 week prior to use.
Water quality is also important for terrestrial organisms.
Various chemical parameters can influence metabolism or growth. For example, a culture of flesh flies is improved when dechlorinated water is made available. The temperature regime for aquatic organisms should be constantly maintained near the organisms natural temperature range. Temperature should not fluctuate more than 1-2 o C. Environmental temperature changes of aquatic organisms should be effected over several hours or days to avoid temperature shock. Continuous light is not beneficial, while indirect, natural day light or artificial light benefits most organisms.