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Discussion Starter · #1 ·
I'm planning to upgrade the lighting over my 36"L X 18"w X 24.5" H tank. Currently, I'm running 2X95W Actinic VHO and 2X95W 50/50 VHO. I could add 2 more 36" VHO tubes (at virtually no additional cost since I've got all the components on hand) or I could replace 2 of the VHO tubes with 175W MH's (probably the 10,000K Ushios. Either way, it ends up being about 550W of lighting, give or take a few watts.

What I'm wondering is what are the pro's/con's of these 2 options? The MH set up would involve considerably more $$ to start up, but I can manage it if I collect the components a little at a time. What about the long-term operational costs vs. benefits to potential tank inhabitants? The hood is 12" tall with 2 4" fans. Would heat be more of an issue with one set up or the other?

Thanx,
Bert
 

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Hi Bert,
I have 2 250 watt MH. They put out a considerable amount of heat but I would think with 2 4" fans that shouldn't be a problem for you. Also MH need replacing every 2 years, not too bad. If I were you I would go with the MH. Even 175 watts are very benificial to coral growth. I'm not quite sure if you mean replacing all of the VHOs for MH or adding MH. If I could I would try to keep the VHOs while adding MH. Right now I have MH and actinics and I'm trying to find a way to add VHOs so that I can have "daylight" in the tank for more than 4 or 5 hours, which is all MHs should run unless your trying to keep an algae tank :)
 

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Austin, what do you mean, "Algae tank" I know people who use only MH so they must run them more than 5 hours. I run mine for 10 hours a day, but then I am having problems with algae so maybe that's part of the reason?
 

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i have the same tank with 2 250w mh and 2 vho's about 3" from water with one 4" fan and my temp goes from 75 to 78 with no chiller but the room temp is at 70. IMO if you go withthe mh 250W are only a little bit more.
 

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Oops! Sorry about that. I meant every year. And yardboy I was running mine for 10 hours a day also and then I talked with my Lfs and he said that that was the problem. I've cut mine back to 4 or 5 and it's subsiding a little!
 

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Algae will grow if it has food. Lighting alone is not food for the algae. Yes, running them 10 - 12 hr a day will develop algae, but not to the degree you mention.

If you are having algae problems look elsewhere for the source. Tap water? Skimmer running sorta? flake food? There are many sources, but these are the main ones
 

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Discussion Starter · #9 ·
OK, but to get back to get back to my questions :) .....

I've got the resources for one of 2 options. One would be 6 X 95W 36" VHO's (half Actinics and the other 3 50/50). The other alternative would be 2 X 175W Ushio 10,000K MH plus 2 X 95W 38" VHO Actinics.

Since both set up's are about the same total wattage, I'm assuming they'd be about equal in terms of heat production and energy consumption. Which bring me to question #1. Are these assumptions accurate? If not which set up would produce less heat, consume less electricity?

Secondly, which of these 2 options would provide the best lighting in terms of quantity (intensity) and quality (spectrum) ?

Right now, my reef is dominated by LPS and mushrooms/polyps. After it has matured a bit more, I'd like to keep some SPS and maybe a clam or 2.

Thanx,
Bert
 

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They will produce about the same heat. MH is localized and easier to exhaust out of the hood. I would try to find out about the output of the lamps not in terms of watts (maybe lumens) to find out how they compare. Some people will say MHs are a must, I believe that it is quantity not source as far as lighting goes. Sounds like your on the right track of upgrading your lights for what you want. Keep us posted when you decide what you are going to do.
 

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Discussion Starter · #11 ·
Well, I did a bit of research and was able to come up with this. According to the technical spec sheet from Ushio, the 175W 10,000K bulb puts out a luminous flux (lm) of 7500. Now, if I had the faintest idea of what that means, I'd only be halfway towards an answer, because after almost 2 hours of "googling", I can find no similar data for URI 95W lamps.

Anybody got any ideas of where reliable, comprehensible info might be found that'd allow a non-physics major to make an informed (if not intelligent) comparison?

Thanx,
Bert
 

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Discussion Starter · #13 ·
Or more specifically, PAR/Watt.... but if anyone has that info, they're not making it easy to find. At least my humble efforts to do so failed miserably.

In any case, I did go ahead with the purchase of 2 PFO 175W pulse start ballasts, 2 Spider reflectors, and a pair of Ushio 10,000K 175W lamps. These, supplemented with 2 95W VHO 03 actinics give quite a bit more light than my previous 2 X 95W VHO 50/50 plus 2 X 95W VHO actinics, and the color rendering is much more pleasing. More importantly, my critters have responded to the lighting change in a very positive way after slowly ramping up the amount the MH's are on over a 2 week period.

I did build a new hood for this lighting set up which is considerably taller at 12" than the hood I had the VHO's in. In addition to getting the MH lamps far enough off the water to make me comfortable running them over an open top tank, it also made enough room for 2 4" fans. In that configuration, the water temp actually drops a degree or so when the lights (and the fans) come on. I've actually had to bump up my heater to keep the temp as consistent as possible, so heat isn't a real issue.

As far as energy consumption, well, the jury is still out. We'll see what the PG&E (Pacific Graft and Extortion) bills look like over time. This much I do know... If I'd added 2 more VHO's, I'd have had 570W of lighting. With the MH set up, there's 2X95W VHO + 2X175W MH = 540W, about 30W less. Whether I'm getting as much (or more) useable light is a question I can't answer, but like I said, the critters are happy. So I am too :)

Regards,
Bert
 

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i'm trying to get idea's for my canopy, did you leave the back or top open at all for heat or is it all inclosed? have any pics as well?
 

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Discussion Starter · #15 ·
Sam,

The hood is a pretty basic 3-sided box using rabit joints reinforced with pegs. The back is essentially open except for a 1"X2" rail across the top that keeps the sides square relative to the front and supports the piano hinge that lets me flip the top up.

The fans are mounted low on the sides and they both blow in. I have in the past mounted fans on the back side of hoods and run them as exhausts, but they seemed to suck up a lot of salt spray in that configuration which lead to early fan failure.

Regards,
Bert
 
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