The colors of astaxanthin: Microalgae have long been grown under controlled conditions in the laboratory, where temperature, pH and other important variables can be well controlled, usually with large amounts of researcher and technician time spent doing it. However, these systems are too small - just a few gallons ñ and the amount of time and effort needed to keep them optimized is too costly, for them to be suitable for commercial use.

The first attempts to produce microalgae on a very large scale were done in "open ponds." The broad, shallow channels in the open ponds minimized the shading effect and could be affordably built at a substantial scale.  However, the tradeoff for achieving an acceptable commercial scale was the loss of control over the growing environment.  Since ponds are open to the atmosphere, many variables, like temperature, cannot be effectively controlled without great expense. Contaminants that can completely destroy the commercial value of an entire crop can easily invade these open systems.

Only a few microalgae have ever been grown successfully in open ponds. These are generally species that can thrive in harsh environments that are hostile to competing species, such as high salinity or extreme pH. Such atypical growth habits reduce the potential for contamination by other undesirable aquatic organisms, but the number of species that can be pond-grown is very few, and they are not necessarily the ones that offer the most valuable products.

Thousands of microalgae have been grown at small scale in the laboratory, proving that with proper controls they can also be grown at large scale.   The obvious solution was a large-scale photobioreactor, but the way to design and operate such a system was not nearly as apparent.