Lighting advice needed

[da6d2003]

I've setup a new tank and have tried a bunch of different lighting scenarios.

Specs.

Tank dims. 84x30x26
1/2" starfire glass
4" eurobrace
(2) 6" wide center bracing

The lighting setup I have now is
(2) 72" VHO actinics
(3) Lumenmax elites running Helios 250w DE hqi lamps running on PFO ballasts.

The reflectors are now suspended 13" off the surface.


By reading the specs on the elites I thought I would be getting a 30" spread of usable light but that doesn't seem to be the case. I'd like to have an even spread of light across the tank but I'm getting shadows from the center bracing and not enough overlap to compensate.

Do you think I need 4 elites to be able to get the coverage I want?

Here is a pic of the right side of my tank. The light is centered over the rock formation. You can see that I'm not even getting much light to the corals in the back and the left of the structure.

Any advice or suggestions???

 

[coral diver]

Yes David a 4th will help with the spread alot and you can lower it by a few inches for penetration upon the addintion of the 4th elite.

 

[stephj03]

Diamond style reflectors come in two classes. 1. Those that focus light down (lumenmax elite, lumenbright) and 2. Those that spread light out (lumenarc, full size lumenmax). The greater number of facets and/or incorporation of hammertone surface on class 1 reflectors promotes a spotlight profile. Thus the peak par achieved by class 1 reflectors beats class 2. But the drop off in par away from the peak is a bit steep, hence your shadows. Class 2 reflectors have fewer facets and limited if any incorporation of hammertone and reflect light "out" and down. For a tank your size, I would add 2 more lumenmax elites if your goal is even light distribution. Alternatively you could swap your LME's for full size lumenmax or lumenarcs (space permitting) or even lumenarc minis depending on mounting height and stay at 3 total reflectors. If you haven't seen it already here is a pretty decent article on the topic of these reflectors.
http://www.advancedaquarist.com/2009/1/review

As a side note I seem to remember hearing that hammertone was used to cut down on hot spots on the bulb so it's affect on the performance of these reflectors may not have been intentional.

 

[Aquafrags]

I think that if you added an extra pendant you will lose the shadowing effect