Need MH lighting reccommendation for 36"x12" display tank

[ScottT]

Basically I have a 55 gal tank (standard 4' long and 12" front to back). I've partitioned off one foot on the right side and use that as my sump/filter (miracle mud style), so I'm trying to light ~ 36" of display tank only.

I am currently using URI VHO but would like to move to a MH setup partially for the glitter lines and so I can keep clams and sps some day (today I only have lps, shrooms, fish, inverts).

I'd prefer to get away with a single bulb setup if possible to curb expenses. I'm open to either SE or DE (HQI) setup but feel I am limited by the 12" front-to-back dimension... smallest reflector I've seen for a SE bulb is atleast 12" and I'm thinking I need the reflector mounted perpendicular to the front of the tank and kind'uv high in order to get close to a 36" light spread.. I'm afraid there just won't be ample space for such a reflector.

I now realize that the DE setups take up less space and may be better for my application.

* Regardless of the setup, I can use my existing IC 660 to supplement actinic if needed (which I am assuming). I'm leaning towards a 10K bulb, but open to suggestions.
* Also, I will build my canopy to enclose everything, therefore I can pretty much accomodate any height needed... but am limited by the 12" width (front to back measurement).
* I know 3' coverage is pushing it, but as long as it doesn't look bad, I don't mind putting my demanding corals in the middle and having the ends for those less light demanding corals.

Here are a couple questions before I ask for your reccomendations:

1. How feasible is it to expect close to a 36" light coverage with a single bulb SE or DE MH setup?

2. Assuming it is feasible, does it depend whether the reflector (SE setup) or pendant (DE setup) is mounted parallel or perpendicular to the front of tank?

Typically I am a major DIYer and therefore I don't mind a retro kit or even piece-milling a setup.. but I do lend towards the cheapest, yet effective setup possible.

Now, what setup suggestions do you have for me? single bulb, dual bulb, SE or DE, 150W or 250W, ..

Thanks a million!
Scott

 

[Jeremy B.]

Hi Scott,

There is a lot of talk on RC and other boards about a single MH bulb only being able to do 2' of tank space. IMO this is definitely not so. You should have no problem lighting a 36" tank with only one lamp. As far as setup goes, you will get a better spread with a mogul base (SE) bulb that is mounted in a spider type reflector, perpendicular to the front of your tank than what you would with a DE setup mounted perpendincular or parallel. The PFO optimal (spider) reflectors are 12" when mounted in this direction, but the actual lamp screwed into the mogul is not the full 12". You should have 2"-3" of play, maybe more depending on which bulb you run. So you could trim your reflector down with no problem. At the width you are covering I would recommend running the actual lamp 10"-12" above the water surface. For setup recommendations, I would take a look at the PFO retro kits using a 10k 250w bulb. I think 175w would be enough for the size you have now, but the 250w is not much more in cost, does not put off much more heat, and definitely gives you more room for upgrades in the future if that bug ever hits you. The Ushio and AB seem to be about the most popular 10k's on the market, and combined with a couple VHO actinic they look great IMO! Let us know if you have anymore questions.

Thanks,
Jeremy

 

[ScottT]

Jeremy,

Thanks SO MUCH for taking the time to provide such an informative and detailed response. Of the responses I've received from a simply post asking the feasibility of covering 36" with a single bulb, I didn't get a single one saying it'd work! I guess with everything else in this hobby, so much is subjective!

The wattage of the bulb is something I want to clarify before I place an order... I've seen various post about "my lights bleached some of my corals", etc... Do I need to be concerned that a 250W setup would be too much for my tank or is there not that much difference between a 175W and a 250W? What if I decided to go with a 2 bulb setup?

Again, thanks!
Scott

 

[ScottT]

One more question:

I've heard of folks positioning the spider or PFO optimal parallel rather than perpendicular... any idea how the spread of light is impacted by this? I've read Sanjay's reflector write-up and in general, the light spread was fairly circular/eliptical.... which would imply there isn't a big difference whether a parallel reflector was used and mounted perpendicular or whether a spider/optimal was mounted parallel... thoughts?

 

[Jeremy B.]

Hi Scott,

For mounting the spider's parallel vs perpendicular, you will get a better spread perpendicular. It might not be much for direct light, but the difference in indirect light is pretty great IMO. You might notice a little bit of a "dim spot" in each upper corner of the tanks mounting parallel, whereas a perpendicular mount (high enough of course) would not let this happen. As far as the "bleaching corals" goes, I wouldn't worry too much if you properly acclimate everything. I have kept mushrooms and softies 8" under 400W MH's before, and I have kept them 24" under 175's with the same results in the long run. It is all about light acclimation, and not shooting them with an enormous amount of light all at once. If you go with a 2 bulb setup then I would just probably go with a couple 175's. Two 250s might be a little more heat than what you want in there.

Thanks,
Jeremy

 

[ScottT]

Everything you've said makes sense to me. Thx!