[coralsnaked]

I think a lot of people are going to have to make changes in their systems to include more nutrients in the water column if they want to run these extreme LED systems that are far brighter than MH systems ever were. I have been experimenting w/ LED - VHO-MH comparisons on my frag tanks. All tanks have a PAR at the surface of ~ 55 and are linked so nutrient levels are basically the same on all three tanks. I run middle of the road on NO3 < .25 and PO4 <.02 w/ a margin of error on both at .02 as I utilize RS Pro testing equipment. So levels could be at times as high as .04 or as low as ~ 0.0, but I believe the avg to be as stated.

I was most interested in growth rates and what I have found is for growth nothing beats MH @ 6500kw, and the jury is still out for best coloration. I have seen nothing to indicate that any of the 3 types of lighting source proved to have any effect on color growth. Not to be confused w/ viewing the corals. But in setting up the system, I did have to initially reduce the intensity of the LED source as it initially produced nearly 70PAR at the surface and hurt the corals coming off the MH system. Now that everything has been in equilibrium for 3 months I will also begin to look at colors and report back to thread in the future after making some small changes in PAR equal to 5 PAR +/- while holding nutrient levels = .