Agree these are great lights, the PAR output is heaps stronger (seneye) on the 300W compared to a Radion XR15 (both lights claim to cover 2' by 2'). Compared to the Radions\high end lights though, 1. they use heaps more electricity (a factor when comparing total cost of ownership over say 3 years), 2. the fan gets noisey as they age when intensity is over half and 3. They aren't controllable so no dim up/down to simulate the daily cycle. Great for frag and quaranteen tanks, a debate for your display based on the number of light fittings you need and your local electricity prices (here in Aus they are insane, I worked out the Radions are cheaper overall in a 3 year timeframe - assuming the Mars aqua can last 3 years)
