The mission of the Mak Pak Scale Up project 2021 present) is to develop a seaweed based food packaging material and to sustainably scale up the production of seaweed, including Ulva spp in a recirculating land based facility supplemented with artificial seawater that requires a selection and optimization of the seaweed of interest The Ulva genus has previously shown high plasticity and capacity to acclimate and develop under broad ranges of environmental conditions, suggesting this may be a promising candidate for production in a RAS with low salinity artificial seawater Selecting an Ulva strain well adapted to such conditions will help reduce the costs of salt and, therefore, optimize production The aim of this study was to determine how salinity can be used and adapted throughout the entire Ulva production to define several key points 1 strain selection 2 nursery and seeding 3 optimized production in adult Ulva and 4 increasing functionality (e g high antioxidant activity) Based on the results of three different experiments, it was possible to conclude how salinity impacts different strains of Ulva (tubular and blade species) from warm temperate environments, during three key moments of their development and with that, conclude which strains would be more suited to be scaled up within the scope of land based production At the same time, the data presented serve as a baseline for further work with Ulva under different cultivation conditions