It is best to increase a tank’s light intensity during these different developmental stages. In its beginning stages, kelp is sensitive to and needs less light. As the kelp matures, light intensity should slowly be increased. There are two ways light intensities can be adjusted:

Using a Photosynthetic Active Radiation (PAR) meter at the beginning of the season can help determine which setting/configuration will omit a certain PAR value (measured in μmol/m²/sec).

If using the mesh-screening method, it is recommended that one screen be removed each week. However, at GreenWave we’ve noticed that some spools may not be as well-developed as others, and taking off a screen too early can cause what we call banding. 

We now only increase the light intensity once we see the next developmental stage start to form. The slower introduction of light may cause slower overall growth in the hatchery, but this approach is preferable over uneven growth on the spools. We always begin with four screens and then remove the first screen after we see gametophytes (around day 10), and so forth, as outlined in the table below. Since implementing this method, we have not seen any vertical banding on our spools.