[j_man]

in order from most to least please list most PAR.......VHO,PC,HO,MH,T5 This way I can be educated before attempting the next series of tanks.

[Reefland]

This is a very difficult question to answer since it really depends on the bulb and ballast combination along with the type of reflector to push more light into the tank. Generally:

MH - Most intense.
PC, VHO, T5 - Some better than others but generally equal.
HO - Least intense of what is listed.

[charlie]

This is one of the reasons I'm not allowed in the my local LFS anymore!!!!

Take a look at any of Sanjay Joshi's articles and you can probably find what you are looking for. What you have presented is extremely vague????? We need to know what you want to do with what you have!!!

Sorry to be so blunt!!

[Meric]

The only problem with Sanjay's Articles is that they only provide PAR values for different types of MH bulbs on Various Ballast. No real comparison against T5, VHO, PC. So if you want to know what MH bulb provides the best PAR then check out Sanjay's articles. IF you want a comparison of different lighting types then that is much harder to find.

And I will disagree with Reefland's category's of Most Intense to least intense (watt to watt comparison). As I see it right now:

T5 with Parabolic Reflectors: 1st
MH - 2nd
VHO - 3rd
PC - 4th
NO - Last

The reason many do not agree with the T5 suggestion is that they have not truly seen them running with the correct reflectors. The prebuilt kits with 6 or eight bulbs come with a flat reflector and the PAR values for T5 on a flat reflector are half that on a parabolic reflector.

Just my .02

[Poseidon]

I'll say that it is true I have not seen T5 in action yet, but I can tell you MH has worked very well for me! I have also used PC and VHO, and MH has been by far the best!

[Reefland]

I have seen them in action and they don't appear to be any brighter than VHO or PC's to my untrained eyes. I would be hard pressed to think that taking some lux readings 20" down in a tank that you would get higher readings from 4-6 T5's than you would under a 250w MH. Again, this is just my suspicion based on visually looking at both.

[Meric]

This came from the Grim Reefer on ReefCentral:

(6) 80W Overdriven T5's bulbs (1 blueplus, 2 Atinic blues, 2 aquablues and a daylight) produced a PAR reading of 145 UMOL @ 18.5" (I assume that he was using individual Parabolic reflectors also)

(3) 250w 14K EVC Metal Halide Bulbs on Electronic Ballast produced a PAR reading of 95 UMOL @ 18.5"

Here is some info I actually did find on T5's. This compares 660 Watts of T5 against 750 Watts of MH @ the depth stated in a saltwater tank.

[charlie]

Doesn't overdriving bulbs reduce their lifetime, which equals more replacements, which equals more money spent trying to do the same thing that a metal halide would do???

[Ninong]

Originally Posted by j_man

in order from most to least please list most PAR.......VHO,PC,HO,MH,T5 This way I can be educated before attempting the next series of tanks.

This question can't be answered the way you are asking it. For example, there is a huge variation in PAR between metal halide lamps of the same wattage just as there is a huge variation in PAR between any lamps, fluorescent or metal halide, of different Kelvin ratings.

Furthermore, you can't really confine your judgment of a lamp's potential value to just its quantitative PAR numbers. You must also consider the spectral distribution of the PAR and how it matches up with known requirements of the various pigments that drive photosynthesis. For example, you might find some very powerful and very inexpensive metal halide lamps at your local home improvement store that would be totally inappropriate for use in a reef aquarium.

I don't think anyone on this board would challenge the assertion that a 1000w metal halide lamp is much more intense than any array of fluorescent lamps or that it will penetrate deeper into the water column, but that doesn't mean it is an appropriate choice for anything other than really large aquaria that are at least 33" tall. On the other hand, trying to light a 48" tall aquarium with anything less than 400w metal halides would be foolish -- 1000w halides would be the best choice for a 48" tall tank that is intended to house SPS and Tridacna clams.

Before you even begin to consider the various lighting options, you have to know the dimensions of your tank and the lighting requirments of the animals you expect to keep. Certainly T5 HO fluorescents with good reflectors would be an excellent choice for most aquaria that are less than 24" tall. Whether they are the best choice for reef aquaria that are 24" or taller depends on what you wish to keep. I wouldn't even think of sticking 250w or 400w metal halides over a tank that is only 18" tall but, on the other hand, I doubt that I would choose anything less than that for a tank that is at least 33" tall.

And, as Sanjay's tests have shown us, not all metal halide lamps are created equal. Some 175w metal halide lamps produce three times as much PAR as other 175w metal halide lamps (i.e., 10,000K Ushio vs. 5,500K Venture). Some 250w 10,000K HQI DE lamps produce more PAR than some 400w mogul base metal halides. And some 400w metal halide lamps can be run for 18 months (6500K Iwasaki) while others (20,000K Radium) lose 40-50% of their intensity during the first year and should be replaced after only 6-8 months.

Maybe if you would simply post the dimensions of the tank(s) you are considering and what you plan on keeping, then everybody could offer their individual opinions on what they would choose for such a setup.

[Ninong]

Originally Posted by Meric

This came from the Grim Reefer on ReefCentral:

(6) 80W Overdriven T5's bulbs (1 blueplus, 2 Atinic blues, 2 aquablues and a daylight) produced a PAR reading of 145 UMOL @ 18.5" (I assume that he was using individual Parabolic reflectors also)

(3) 250w 14K EVC Metal Halide Bulbs on Electronic Ballast produced a PAR reading of 95 UMOL @ 18.5"

Here is some info I actually did find on T5's. This compares 660 Watts of T5 against 750 Watts of MH @ the depth stated in a saltwater tank.

I just ran that 250w 14,000K EVC metal halide lamp through Sanjay's search function and it has the worst PAR numbers of any 250w metal halide lamp on the chart. In fact, it has only about half the PAR of some other 250w 14,000K metal halide lamps. Comparing it to 250w 10,000K metal halides shows that most of those have 3-4 times as much PAR.

I wonder what the numbers would be if that guy compared T5's to a decent 250w 10,000K metal halide lamp?

[j_man]

Sorry I posed such an insane question. 1st if all things were equal on quality of light and source. what would work best on a 28 inch deep tank with stonies in order of best to worst. I ask only because I would like to start setting up some larger tanks, and I hate MH. Too hot and freaky for me.

[Poseidon]

Hate is an awful strong word, especially for what is most widely used by successful Reef keepers. There are SOME who keep SPS with T5, but from what I have seen they use SO MANY that they mine as well have gone with MH and saved the space and hassle.

Have you tried MH in the past? I suspect not, or else you would not have asked. Once you have a MH fixture I don't think you will ever use anything else!