125 gal MH lighting questions

[jag3365]

Just a few questions for you guys as I am looking at upgrading to MH.
Background: I have a 125 gal (6'x18"x24") with a DSB of about 5" or so. Tank is just starting and I have 2 6' VHO lights currently, 1 actinic blue and one actinic white.
So I want to do MH for future critters and corals. I am not sure what I want to do, but I'd like to get whatever I need so if the time comes I won't be short. So I am looking at getting retrofit lights, 2-3 and I'm not sure the intensity. Will 175 work or 250?
Also is there any site or pictures so I can find out what spectrum I should look at? I don't know what the difference is between a 7500 degree bulb and a 20000 degree bulb. Any info would be appreciated.

 

[golfish]

You'll need 3 bulbs to cover the whole tank. If you don't wanetd be limited you might as well go with 250's.

 

[jag3365]

Been looking around. Do most people use the 10k bulbs for the most natural light to supplement the actinics?

 

[rangermonroe]

I disa gree with golfish on this one, I think that two bulbs is sufficient.
If your tank is like mine, it has a center brace which will reflect a lot of light from the center bulb, not to menytion if you keep your junk on it like I do mine.
Yeah, there is a small area of "shadow"...I keep my ricordias here.. but I thinks its OK. I think that it would be similar if I had one over the center anyhow...and my fish food would get really hot to boot.

 

[golfish]

Originally posted by rangermonroe
Yeah, there is a small area of "shadow"...

Originally posted by golfish
You'll need 3 bulbs to cover the whole tank. .
So you "disa gree" with what?

 

[jag3365]

The 125 AGA has 2 center braces up top. So 3 might be better. And what do you keep up on your brace above your tank? I am confused. Nothing will go above it but a canopy and lights.
Can you use too much light? Will 3 250s be too much? I know the tank is 24", but there is a good 5-6" of sand on the bottom. Does this really make a difference guys?

 

[rangermonroe]

I can't disagree with you?

This is what I am saying... If you have a center brace, (esspeciallly if you stack stuff like I do) than the center bulb is irrelevant.
Yeah, I have a shadow. It may be from the misising 250K, but I'm guessing that the can of flake may have some input(or output
.

 

[golfish]

I'm just not sure what you disagree about. Its pretty much a given that Jag's going to need 3 bulbs to cover the whole tank. Sure, heyou can get by with 2 bulbs (not with two cross bars) but, like you said, "I have a shadow"..I didn't say he needed 3 bulbs. I just said he needed 3 to cover the whole tank.Hec, you can run one bulb, just hang it high
If he had only a single cross bar in the middle then two bulbs would be ok, not great but ok.
As far as cross bars go, well, that's why I always suggest Euro bracing. My old 4 foot long 150 had a 16"wide cross bar on it (man I hated that thing) I ran two 400 watt Radiums on each side of the cross bar and a 400 watt Iwasaki or 10K Ushio over the cross bar. Those bulbs did an ok job cutting through the 1/2" glass. Without that bulb over the cross bar the tank had a huge V shadow right in the middle.

 

[rangermonroe]

I think that two bulbs is enough. If you use three, then you have a hot shelf in the middle with a shadow under neath it, and the whole point of having more light is lost...but hell, I have another 2.1 watts per gallon.
What i disagree withis the fact that we "need" 1 bulb for 2 feet of tank length.
If you have a center brace , as I do, is not the benefit of that bulb lost?
The shadow that I have mentioned, and seems to be a fixation, extends about 6 inches into the water and is 6 inches wide at the top. It is not ablack hole, and only the Knowing Know that it is there.
If I had placed another bulb over the center brace, I would have hot fish food and a somewhat lighter shadow...but a shadow, nonetheless.
I think that two bulbs is enough.

 

[jag3365]

You're not listening to me. I have no center brace. I have 2 braces equal distance throughout the tank. So there will be NO shadow.
will 175 be enough for the 6' long tank. Or do I have to go to with 250 to get the good effect?
And what degrees bulb gives the most natural light?

 

[golfish]

Originally posted by rangermonroe
What i disagree withis the fact that we "need" 1 bulb for 2 feet of tank length.

I never said anything about 1 bulb per 2 feet. I said he would need three bulbs to cover the whole tank. You pretty much said the samething. However, your not reading what Jag has written (more then once) With a center brace two bulbs would be just "ok" . With two braces 3 bulbs are a must.
Jag,
Heat will probably be an issue with 175's, just not as much. If you do things right and keep the tank room cool you can probaby get by without a chiller. If you decide that some day you'll want to keep sps then 175 wont get it. You'd have better looking sps with 2x250's then you would be with 5x175's. Remember, WPG means nothing.
Originally posted by Jag3365
And what degrees bulb gives the most natural light?
I'd say the 5.5 or 6.5 K's but those are pretty ugly. Even the 10K's are yellow. Depending on the ballast the 20K's might be too blue. If you ran 3x250 watt SE Radiums on an HQI ballast you'd love the light. IMO, its the best looking MH's out there.

 

[dzones]

Well just to add my opinion to the lot...
I have a 125 as well and I am using a 400W MH 14K Radium at each end, and an actinic pc as well, and I have the center lit with dual 24" corallife 96W lights with actinics and 50/50 bulbs.
I started with just the two 400's thinking it would be enough but realized after I had a very dark center. I could not afford the space for another ballast (and at the time financially could not afford it) so went with the pc's instead. Fortunately the design of my reef tank you cannot really tell too much that the center is not as well lit. I used the dual mountain range with a center channel setup and use the center for some of the more simple light requirements.

 

[rangermonroe]

Jag, Golfish is right, 6.5 k will give you good growth, but IMO seem very yellow/green. I used an Iwasaki 250, but ran actinic with it for asthetic reasons.
I now use a 10k xm and am happy therewith.
I would go with the 250 watts over the 175. I don't believe that the setup cost is dramatically different between the two.
Bulbs cost about the same.
It is cheaper to buy balasts once, rather than upgrading later on.