3reef witnessed an interesting demonstration by PFO lighting recently that compared the PPF PAR output of a PFO Solaris LED aquarium light fixture to a PFO 400w halide fixture using a 15k XM bulb. The LED Solaris Lamp Demonstration by PFO Click for large pic to read meter results. This arrangement was to show that the Solaris LED fixture actually had a higher (PPF) PAR rating than the 400 watt halide bulb. Note: 3reef told the XM bulb used in the demonstration was less than a day old. The Setup: Each fixture was hung at the same height (rather high - approximately 18 inches) over the same 25" deep cube aquariums. Each aquarium had a sensor for a Apogee Quantam Meter (Model QMSS-E) at the bottom of the aquarium. The Apogee Quantam Meter Model QMSS-E Used in this demo Further info on PAR and the Apogee Quatam Meter: http://www.apogee-inst.com/pdf_files/QuantumMeter_Manual.pdf Apogee Instruments: Frequently Asked Questions Observations: The LED Solaris fixture clearly was getting a higher number on the Quantam Meter - nearly 20% higher than the 400 watt halide fixture. 143 to 115. These numbers did not change much over the course of the day 3reef witnessed this setup. Beyond the numbers, 3reef, having never seen a Solaris LED fixture in action, was impressed by the light spectrum of the LEDs as seen by this observer's eyes - crispy white with a blue tinge. PAR AND PPF: Although told that these sensors were measuring PAR (Photosynthetically Active Radiation), research indicated they were measuring PPF (Photosynthetic Photon Flux) PAR. The April 2008 issue of FAMA magazine describes PAR: A breakdown of PAR AND PPF from Sun Master Grow Lamps: PFO on it's LED SOLARIS Aquarium Light Fixture: A recent 3reef discussion on PAR: http://www.3reef.com/forums/reef-lighting/par-lux-meter-45699.html Final thoughts: 3reef's Matt Rogers is not the brightest bulb in the box so to speak. So talk of falling photons had his eye's glazed over for a while. But boiling it down. Way down.. It seemed that the LED Solaris fixture was producing more light that could be used by corals going by the numbers shown in this demo. Is that enough to offset costs? Hmmm.. well this could turn into the hybrid car argument which is highly debatable as well. But what the numbers clearly show is that LED light fixtures should not be quickly discounted as a gimmick or fad. That perhaps there are some real merits to an LED light fixture for the aquarium after all. What do you think? Has this demonstration changed your opinion of the LED Solaris fixture? Or the future of LED fixtures for aquariums? Tell us why.