[ccLansman]

Thanks for the info CalmSeasQuest. When i first switched from a 250W MH over my 55gal to the led fixture I used my par meter to first get readings with the MH. I then tried to match those same par #'s with the LEDs... Suffice to say the coral were NOT happy. The output is definitely not the same. I ended up moving the fixture over a foot off the tank and dimming it down about 30%. I measured again and the par was around 200-250 with the MH about 3/4 down into the water. I have the leds at 100-150 @ 3/4 the way down now and the coral seem much happier. So i agree that there must be some amount of error with par meters and led. The thing i don't understand is the fact that the par meters are supposed to measure light from 400nm-700nm.. I guess with our LEDs being in the 420-440 range its close to the cutoff. How does Sanjay know there is an error %? If the only way of measuring the output is par meter and the par meter is off how was he able to verify his results?