This puts or floats the plants in water containing nutrients into a container. The water is renewed by a control system to prevent the plants' roots from becoming dry. The water does not flow through the container but remains static. Because the water is still algae often grows, using nutrients and covering the plants roots so that they are not able to take in the nutrients so well. Algae growth can be reduced by using some method to prevent light from reaching the roots, for example, black plastic, or aluminium foils. The static solution has to be changed every week or two to ensure it has the correct amount of nutrients.