300w VHO vs 250wMH

[Modo]

The bulbs I would run on either setup would be...

VHO: 2 Actinics, 2 Daylights (6500K)

MH: I would run an Iwasaki 6500K and try and supplement with NO actinics that I am running now. Which would actually bring the wattage up to 290w (would not be able to fit 4NOs with a MH over the tank).

Thanks...

 

[bigtank]

With that VHO combo and MH bulb, the 250 wins hands down. It will put out nearly double the light. If you want SPS, the 250 is the way to go. Many LPS will like it just fine also.

 

[SPC]

I would agree with all the above except for (sorry Guy) the heat factor, the MH are much hotter!
Steve

 

[Iron]

If you used 1_250w 10k without vho vs 300w vho. The halide will produce better growth and still look good to the eye. You maynot like Iwaski6.5k without vho but probally have better growth.I had a 55g with 4_440w vho Put the same corals in a 120g with 2_250w 6.5 without vho. Until i got the whole tank set up. It was like that for a few mo. Same corals grew way faster in a bigger tank with the halides. JME I would use 2_vho and 1 halide you will like the set up

 

[Len]

SPC,

If the 250 MH is much hotter then the 300W VHO's, that would tell you that the MH's are grossly less efficient, and possibly produce less light then a equalivalently powered VHO setup. Energy has to be expressed, either as heat or light. IME, canopy temp with one 400W MH is about the same as 440 watts of VHO.

 

[Modo]

Well, I would love to run with the MH and VHO supplements but I have limiting factor...cash.

I can get the VHO setup or the 250w MH setup for just about the same amount. The 250w comes with the 6500k Iwasaki. Until replacement time for the MH bulb (which I could go the 10k or 20k route) I could supplement with the NOs I am already running.

Has anyone supplemented a 6500k with NOs? Would they even make a difference if all bulbs were actinic? Or would the MH wash out all the blue spectrum?

 

[Len]

Go the MH route then. You can supplement VHO in the future, when finances allow.

The 250W will pretty much wash out all the actinics, aestheticaly speaking. However, I'd still run a pair (or 4?!) actinics; even though it's washed out to your eyes, the tank's inhabitants will still be able to use the additional light.

 

[Modo]

Great guys, thanks!!

I knew if I posted this question you guys would twist my arm in the right direction. I just cringed in the beginning to post ANOTHER lighting question.

Now off to the drawing board to sketch a new hood......

 

[SPC]

Leonard, my point was that 440 watts of VHO are spaced over 4', one 400 watt MH wont light this area, so you would need a 400 watt MH + something for the other 2'.
Steve

 

[Modo]

I'm really not clear on wavelength and PAR and would like some clarifaction.

Would running a 250w MH be more beneficial (to SPS and LPS) than 300 watts of VHO (4 24" tubes)?

The tank in question is a 30x12x18 (29g)tank. Also, in question would be the heat factor. Would running VHO actually be more beneficial due to the high heat intensity of MH over such a small tank?

 

[Anonymous]

This is probably a controversial post, but I'll give my opinions.

Heat - I think you'll find that the total "heat under the hood" is going to be similar between the VHO nad MH.

PAR - Depends a lot on the bulbs you're going to use. Most MH are going to deliver more PAR at the bottom of your tank than the VHO will. The VHO is going to spread the light evenly across the tank, MH is going to have an area directly under the bulb with very high PAR.

I would think LPS would love the VHO and SPS would be better with the MH. But like I said, a lot has to do with the specific bulbs.

 

[Iron]

440w of vho = same as 400w halide. I doubt that. I had 440w of vho and my 1 250w Iwaski had better grow than the vho. When I had my 55g set up it had 440vho I ran 1 250w Iwaski then 2 just to get the corals acclimated in the tranfer. Over a 4mo time. I had both tanks set up and bouth the stuff slow. Anyway I had more growth in 2mo than I usually had in a year with all my softies. Softies I keep for over many years so I could pretty much predict its growth rate. You can check the links and see that 400w any bulb puts out way more light than 440w vho. I'm not saying having a tank with vho is bad but comparing 440 to 400w halide being equal I have to double that. The watts maybe equal the the par isnt.I could find all the ## but to much trouble. Just need to see a tank with 400w with the vho on and off to compare. My vho isn't even a match for my 250. i use both on my tank

 

[SPC]

Iron, I have read over this thread twice and don't see where anyone says VHO is equal to MH in intensity, par, etc... my point was the total heat under the hood on a 4' span.
Steve

 

[RichMacys]

I bet you would have better coloration of the sps if you used just VHO though. And.... Im not sure youve ever turned your Act 03 bulbs on after the Metal Halides are on. I notice 20 watts of Actinic when I turn them on. I run a 400w 6500k and a 10000k 175w on my tank with the 20 watt actinic for the little more tinge of blue I like. Halides are for growing, VHOs are for color. Thats my story and Im sticking to it.

 

[Iron]

I must have missed that some how. The heat from 1 250w will be more than 300w vho but a simple fan will solve the problem The 250w halide would be alot better if you have the room to house one. The halide will give more growth and it will give the corals good color. The vho may look better to your eyes but alone the corals won't color up like under mh. But I use both