Abstract: Apparatuses and methods for growing filamentous algae are disclosed. An apparatus comprises vertical surfaces such as plates or tubes which are suspended above the fill line of a water tank. Surfaces can have a frosted texture for algal growth. The surfaces are kept moist by pumping water from the tank through spray bars to the surfaces. Sprayed water drips back into the water tank. Algae growing on a surface can be processed into products such as biofuel and glycerin. Aquatic animals such as fish can be grown in a tank. An aquatic animal can generate nitrogenous waste as nutrient for algae, and provide food for human consumption. The amount of harvestable algae produced by an apparatus can exceed the amount produced from other systems of comparable size over comparable durations. An apparatus can also be utilized to scrub CO2.