The DE lamps where coral vue 14K 250w(before Reeflux) and coral vue electronic ballast(which I still use, but with SE Reeflux lamps. I use a light meter that measures foot candles, when the lamps where new I read 3800 ftc at the water level and when my SPS crashed I read 1500 ftc. And you could not tell the difference by looking at it, there was not a color change in either lamp, nor could you tell the lamps had lost so much.