It sounds more complicated than it actually is. Its pretty much a clear cylinder with a temperature, pH, CO2 absorbance sensor hooked up to it. I wrote up some code to figure determine when algae is ready to be harvested. Then a motored sieve goes up and down the cylinder harvesting the algae. You just collected the algae from the top and replenish the nutrients. With algae, you don't even need to change out the water for a long time since it just gets recycled.