WISRD Research & Engineering Journal

Figure 25. Kessil A360 Spectral Controller X. The Intensity setting adjusts the amount of light produced by the LEDs, which is crucial for the zooxanthellae. We created our program based on the Preset that comes installed on the Kessil Spectral Controller X. As of this publication, we are using indicators such as coral coloration, visual extension of polyps, and recommendations by coral hobbyists to determine the best settings for intensity. When we can easily quantify the growth rates of coral fragments, we will adjust our lighting parameters accordingly. 3.2.2 Photosynthetically Active Radiation A common method for determining light intensity is to use a photosynthetically active radiation (PAR) meter; specifically, we measured PAR with an Apogee Underwater Full Spectrum Quantum Meter (Fig. 28.)

Figure 26. Left: Apogee PAR meter. Right: Apogee PAR meter in use. 3.3 Lighting Schedule

Adjusting lights is a deliberate process and must be done in small increments to avoid shocking or bleaching the corals. We have been adjusting the lights for months and will be using the schedule shown in Figure 29 for our experiments beginning in 2022. We ramp up the Kessil LED bulbs for 3 hours, maintain a maximum of 6 hours, and ramp down for 3 hours. See Table 3 for specific lighting schedule used.

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