The purpose of this thread is to discuss the possible advantages and limitions of pulse / intermittent lighting using LEDs for reef aquarium lighting applications. This includes
1. Aquarium main lighting.
2. Frag tanks.
3. Refugium and turf scrubber lighting.
4. Phytoplankton culture.
The science of pulse lighting :
"Photosynthesis does not need to take place in continuous light. The solid state nature allows LEDs to produce sufficient photon fluxes and can be turned fully on and off rapidly (200 ns (yes nanoseconds!), which is not easily achievable with other light sources. The off/dark period means additional energy saving on top of the LEDs' low power consumption."
"Tennessen et al. use LEDs to study the effects of light pulses (micro- to milli-second) of intact tomato leaves. They found that when the equivalent of 50 μmol photons mp−2 s−1 is provided during 1.5 μs pulses of 5000 μmol photons mp−2 s−1 followed by 148.5 μs dark periods, photosynthesis is the same as in continuous 50 μmol photons mp−2 s−1. Data support the theory that photons in pulses of 100 ps or shorter are absorbed and stored in the reaction centers to be used in electron transport during the dark period. Pigments of the xanthophyll cycle were not affected by pulsed light treatments. This research suggests that, instead of continuous light, using effectively calculated intermittent light (which means less energy consumption) might not affect the plant production."
From the journal : High-brightness LEDs"”Energy efficient lighting sources and their potential in indoor plant cultivation (2009).
Thereby plants, corals , macroalgae , phytoplankton could achieve same/increase grow with significant reductions in electrical energy consumption. For example you could reduce your lighting cost by 50% by using a 2-3khz pwm signal on 50% duty cycle to a PWM dimmable led ballast.
However ambient light would significant effect the benefits from such a set-up ?
References
Red and blue pulse timing control for pulse width modulation light dimming of light emitting diodes for plant cultivation
(http://www.sciencedirect.com/science/article/pii/S1011134411001096)
Effects of Frequency and Duty Ratio on the Growth of Potato Plantlets In Vitro Using Light-emitting Diodes
(http://www.personal.psu.edu/u0y/nanoreef/papers/360204hs.pdf)
Effectiveness of Flashing Light for Increasing Photosynthetic Efficiency of Microalgal Cultures over a Critical Cell Density
(http://www.bbe.or.kr/storage/journal/BBE/6_3/6695/articlefile/article.pdf)
1. Aquarium main lighting.
2. Frag tanks.
3. Refugium and turf scrubber lighting.
4. Phytoplankton culture.
The science of pulse lighting :
"Photosynthesis does not need to take place in continuous light. The solid state nature allows LEDs to produce sufficient photon fluxes and can be turned fully on and off rapidly (200 ns (yes nanoseconds!), which is not easily achievable with other light sources. The off/dark period means additional energy saving on top of the LEDs' low power consumption."
"Tennessen et al. use LEDs to study the effects of light pulses (micro- to milli-second) of intact tomato leaves. They found that when the equivalent of 50 μmol photons mp−2 s−1 is provided during 1.5 μs pulses of 5000 μmol photons mp−2 s−1 followed by 148.5 μs dark periods, photosynthesis is the same as in continuous 50 μmol photons mp−2 s−1. Data support the theory that photons in pulses of 100 ps or shorter are absorbed and stored in the reaction centers to be used in electron transport during the dark period. Pigments of the xanthophyll cycle were not affected by pulsed light treatments. This research suggests that, instead of continuous light, using effectively calculated intermittent light (which means less energy consumption) might not affect the plant production."
From the journal : High-brightness LEDs"”Energy efficient lighting sources and their potential in indoor plant cultivation (2009).
Thereby plants, corals , macroalgae , phytoplankton could achieve same/increase grow with significant reductions in electrical energy consumption. For example you could reduce your lighting cost by 50% by using a 2-3khz pwm signal on 50% duty cycle to a PWM dimmable led ballast.
However ambient light would significant effect the benefits from such a set-up ?
References
Red and blue pulse timing control for pulse width modulation light dimming of light emitting diodes for plant cultivation
(http://www.sciencedirect.com/science/article/pii/S1011134411001096)
Effects of Frequency and Duty Ratio on the Growth of Potato Plantlets In Vitro Using Light-emitting Diodes
(http://www.personal.psu.edu/u0y/nanoreef/papers/360204hs.pdf)
Effectiveness of Flashing Light for Increasing Photosynthetic Efficiency of Microalgal Cultures over a Critical Cell Density
(http://www.bbe.or.kr/storage/journal/BBE/6_3/6695/articlefile/article.pdf)
