The main Algavi activity is the manufacturing of calcified seaweed: Lithothamnion.
Lithothamnion or Lithothamnion calcareum Sp is a calciferous seaweed extracted 10 to 20 meters below sea level, on seabeds of Finistère. This algae concentrates the seawater minerals. It also contains a great quantity of trace elements that are essential for the neutralization and mineralisation of drinking water and for the animal and vegetable metabolisms.
The name "Maerl" means in Breton language a mixture of sand, crushed shells and Lithothamnion, naturally laying on seabeds.