400w x 6 bulb height

[charcharodon]

I would appreciate some help with bulb height over the water's surface. There are 6 400w 10k's operating over a 480-gallon system. It is nearly 42" deep. The top of the reef is roughly 22" from the surface since the tank is viewed from both sides. Although some of the Acroporas seem to do exceptionally well with the bulbs 6" - 8" above the surface, others exhibit symptoms of excessive exposure. Should I increase the height or switch to 12k or 14k bulbs or zone the system using a combination of both?

[scarter]

I run my 400w about 13-14 inches off the water. keeps me from using a chiller. I was running the chiller almost constantly with them 6 in off the water, now the chiller is off line and not in use. not all the SPS can handle the direct 400 IME. most of the mont can hande it in my tank. I usually start all the corals near the bottom and work them up slowly till I see the color start to fade or change then I drop them about 6 inches from that point. this gives me the best results. some have the best color at the bottom of the tank. as for kelvin. I run 20k radiums on Icecap balasts. not as blue as the other ballasts. SOmetimes I run the 6500 but not often, I cant stand the color. for some reason the SPS dont seem to care about the kelvin IME. but the softies and LPS cant take the 6500 for very long.
HTH

[charcharodon]

I appreciate the input Shane. Now if I can just convince my client to go with a bluer bulb.

[scarter]

just a side note, but the reef you describe is only about half as high as the tank. I think most people find a higher reef more visually pleasing. I dont know how thw tank is set up but maybe a more condensed reef that reached a little higher would look better and afford more choices for coral height.
what ballast are u using?
color(kelvin), is a personal choice IMO, I dont think you should push your client to choose a bulb that you prefer.
if you could talk him into buying a single bulb you could swap it for one of the 10k and fire that one alone to see if he likes the color in his reef, if you want to persuede him, stick a GSP under the 20k and he might like the neon color.
Please, do not take this as a negative response, but I have set up systems for others in the past and regret trying to push my prefrences on them.

[charcharodon]

I've considered augmenting the rock stack (which I did not originally install) to include at least one peak slightly off center that reaches within a few inches of the surface, but a having to move dozens of specimens to accomplish this has made it easy to put off. The system is VERY well-stocked.