good idea
Even less heat and plenty of air circulation. I think you will find that your fan or fans will hardly have to come on. I am going to do a test with my current Lumenmax reflector by Sunlight Supply(7" ultra mini) which I usually keep at 8"-9" off the water. My fan currently comes on 10 minutes after the light comes on using an RK2. I am confident that when I swap out with a new LumenBright mini set at 14" that my fan will come on 2-4 hours after the light comes on just like it does in my main display.
As qouted by jnarowe, "I think the LB would fry a 20" deep tank." I could not agree more if you set these reflectors with bulbs 8"-9" off the water with a 250w or 400w bulb. This has been the crtical point since the beginning of this thread. These reflectors are really strong.
From all of the tests I have done under both Lumenarcs and Lumenbrights, I can honestly say the difference in intensity is not 16% but more like 30%-35%. Lumenarcs were not meant to be so high off a tank. And in fact Lumenarcs were not even designed for the reefkeeping hobby but for agriculture.
The LumenBright reflector was designed specifically for the reefkeeping hobby with historical knowledge of all the heat issues reefkeepers have faced with many reflector choices that need to be so close to the surface of the water. The point in designing these reflectors was to keep the bulb away from the water but still add some punch to anything available to reefkeepers today.
Glixtrix showed some impressive numbers with 3-175w bulbs 11" off the water. If he raises them 1" or 2" he will have great numbers still and not have to worry about frying his tank as we are talking about 175w bulbs.
Ganjero, for your application, having them 14"-16" with 16" being optimal for your 5ft tank - you will not have any problems at all with frying coral and have plenty of light from 2 -250w bulbs depending upon the manufacturer of the bulb and ballast combination. Because you will have an open system, you wil have the luxury of easily raising and lowering your reflectors to see for yourself what is optimal also knowing that by raising a LumenBright you don't have to worry about losing so much PAR as it still will drive the light into your tank.
I have been hearing a lot of talk on RC about frying coral and I have to ask myself why so many reefkeepers are having trouble? Is it their water quality? There temp swings dramatically? They have very little flow? They don't feed their coral enough? There bulbs are so close to the water? and probably most importantly are they patient enough to wait 2-3 weeks to slowly move that coral up into the water column where the PAR will certainly increase to assure they don't bleach their coral.
With patience and an understanding of the specific coral in your tank, you can properly acclimate a coral to be able to show multiple colors like this quad or quintcolor mille that is 20" away from the bulb as well as all these other coral on this pillar. In my opinion, lack of patience will fry you
