Q: Lighting Question (135g MH)

[ministry]

I have an 135 Gal tank: <span style="color: #008080;"><span style="font-size: 14px;">72.5 x 18.5 x 25

</span></span><span style="color: #008080;"><span style="font-size: 14px;">I am currently lighting with two 250w 5500K MH bulbs.</span></span><span style="color: #008080;"><span style="font-size: 14px;">

</span></span><span style="color: #008080;"><span style="font-size: 14px;">All PFO reflectors and ballasts
</span></span><span style="color: #008080;"><span style="font-size: 14px;">
</span></span><span style="color: #008080;"><span style="font-size: 14px;">I have a wide varity of coral and life and need assistance hammering out a lighting regimine for my tank.

I would like to add some blue to the profile to give things a nice look.

I would like to stick with MH.

I have an additional 250w MH ballast, an XM 10K, a Ushio 10K and two Ushio 20K bulbs.

The tank has a glass brace in the middle.

How can I best setup the lights (orientation) and timing to provide an optimum environment for my marine friends?

What would you do if you were a frugally minded minded person?
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[george]

I'd put the lights centered over each 2' section of the tank (all 3 lights). Since the center brace is glass, it shouldn't block much light as long as you keep it wiped off. 2 250's really isn't enough to effectively light a 6' long tank.

As for which bulbs, without buying more bulbs, I'd personally go for the two 10K at either end and the 20K in the middle. However you could also go for a gradient effect which would simulate an interesting "increasing depth" effect and go from a 5500 to a 10K to a 20K across. 5500 bulbs aren't really optimal for reefs, however since they put out a significant amount of algae friendly light in the yellower spectrum instead of the bluer frequencies favored by the 10K and 20K bulbs which are closer to the spectra that corals get in deeper water.

 

[ministry]

I agree with your spacing suggestion, There is certainly a gap in the lighting with my current two light system.

The gradient is something I have not considered but would allow for limitless options to tune the coral in to the light they like best....

But what about timing... Under the gradient scenario should they have any staggered on/off for any reason?

I'm also not opposed to purchasing additional bulbs if it makes for a better environment for the tank life...

 

[george]

No special timing is necessary.

If you're willing to buy, then get another 10K bulb and use 3 10K. Eventually, you might want to get some actinic T5 bulbs to supplement. You could also go with 3 20K bulbs, if you prefer that look. Both setups will let you keep anything you like.