Metal halide or T5
 

I was thinking about upgrading my lights and I was wondering what I should do? Could anyone tell me the main difference between the 2? I thought no other lighting could produce the natural colors like a halide and aren't they the brightest?

the more important question is what corals/inverts/livestock would you like to keep? either would work just fine depending how many bulbs you go with/ or what wattage but it is dependent on what livestock you plan on keeping. halides create a shimmer that is more realistic, which is a major selling point, however they cause more heating issues and use more electricity. t5's in general dont produce as much heat, and use less electricity. i dont think t5's look as realistic, and dont produce shimmer lines, but it has its benifits.

T5s and MH produce the same heat watt for watt but T5 tends to deliver less heat to the tank. My MH setup actually runs significantly cooler than my old T5 setup (even though it is three times the wattage) but I assume my results are not typical.

I ran T5 for a year and a half and ended up not liking them.

T5s DO produce shimmer lines. I have T5s AND shimmer lines. :D

I did this research and concluded that T5 is fine for just about everything except the most light-hungry SPS corals. I've got 8x48" T5s on my 4x2x2 reef tank and it is bright. One good fan takes away enough heat that I don't need a chiller. T5 heat is mostly convective, but MH heat is mostly radiative. Fans don't do too much to cool MHs.

Another point to consider is mounting. I have a pretty short distance between my canopy and the tank -- I *had* to do T5s. MHs require a fair bit of room -- most people pendant-mount them.

Dan

well, I dont have a canopy and I was thinking about getting a coral life aqualife pro [url]http://www.marinedepot.com/ps_ViewItem~idProduct~ES53504.html[/url]

I can mount it right on my tank and I am getting a good deal on 1 from a friend. I figured it would be ok without a chiller since it is only a 150 and has 3 built in fans and I will add 2 more to blow on the surface.

Also, whats going to make my borals grow faster?

Whats a boral? :) lol
Any way I had a t5 setup and switched over to MH. I love MH's way better. IMO go with the MHs.

Go MH.. it will cover all your current/future coral needs. Heat won't be a factor since you don't have a canopy. I have 2x150 MH w/ T5's (Current USA Outter Orbit) and don't use a chiller. You will evap a lot of water but that's easy to deal with using auto-top off.

[QUOTE][i]<a href=showthread.php?s=&postid=11495799#post11495799 target=_blank>Originally posted</a> by DanInSD [/i]
[B]I did this research and concluded that T5 is fine for just about everything except the most light-hungry SPS corals. I've got 8x48" T5s on my 4x2x2 reef tank and it is bright. One good fan takes away enough heat that I don't need a chiller. T5 heat is mostly convective, but MH heat is mostly radiative. Fans don't do too much to cool MHs.

Another point to consider is mounting. I have a pretty short distance between my canopy and the tank -- I *had* to do T5s. MHs require a fair bit of room -- most people pendant-mount them.

Dan [/B][/QUOTE]

Im finding that T5s can light even light hungry corals with great results. I have some acros that wont light up under Halides unless they are right under them (PAR levels in the 500+ range), but will light up even more under 300-350 levels with the T5s.

The only thing I can attribute it to is the same thing that causes LPS to sometimes 'shrivel' under T5s... the superior spread of T5s. Less shadows, better spread and even coverage. With halides, I would notice that much of the coral surface tissue had a shadow cast over it at one time or another, but with the T5s... the entire surface is lit up. So perhaps the lack of intensity in some areas with T5s is made up for with the spread. For corals, Im sure they find this more natural as well.

As for heat, T5s and halide make about the same amount of heat, convective and radiant (I hope you arent running your bulbs so they conduct!!!). With radiant heat you cant help too much beyond blocking out spectrums that arent needed, IR and UV. These methods tend to block out the visible light radiation as well though so its really a crap shoot. Phosphor lamps tend to make more IR, but almost no UV... Halides make little IR, but a bunch of UV in most cases.

Either way, arguing which heats the water more is a mute point as you might guess. Both produce about the same heat per watt, and what makes or breaks a given system is how vent it. I put a Tek fixture over a tank w/o fans, and sure enough, it overheated the tank more than an equal wattage halide setup in the same room. How? Well, the T5s created a pocket of hot air above the tank water, heating things up. The halide lit tank had the pendant only covering about 1/2 the water, so the rest of the water was left to 'breathe' rather than heat up.

I see people with enclosed canopies and halides then wonder why their tanks are overheating... well duh!

I think the perception that T5s are cooler than halides comes from them more commonly having active cooling (fans) built in, as well as their more frequent mounting in a fixture rather than canopy/hood/etc. When you look at most halide systems out there, they lack fans. But trust me, if you were to hook up a ducting kit to your halide pendants, you would see how cool they can be. Of course, the other reason for the perception that T5s is cooler is because they have about 40x the surface area per watt to transfer heat over... as a result, at any given point they are cooler to the touch than a halide, of course. But the net heat of either system per watt is about the same.

Whats best for your tank? Well... depends on the tank dimensions (as well as what you want to keep of course) mostly. A 2' cube is a different story than a 55g, you know? One is better with a single halide pendant, the other with T5s.

The reason T5s are cooler than MH, well, they aren't cooler...but feel cooler and don't cause heat problems with the tank.....is because the heat is spread over the length of the bulb with both T5 and MH. Considering that the T5 bulbs are longer, the heat is spread over a larger area. MH don't get any hotter than T5 but the heat is condensed into a smaller area.

[QUOTE][i]<a href=showthread.php?s=&postid=11495571#post11495571 target=_blank>Originally posted</a> by Myka [/i]
[B]T5s DO produce shimmer lines. I have T5s AND shimmer lines. :D [/B][/QUOTE]

How did you make a flourescent tube shimmer?

[QUOTE][i]<a href=showthread.php?s=&postid=11496920#post11496920 target=_blank>Originally posted</a> by tkeracer619 [/i]
[B]How did you make a flourescent tube shimmer? [/B][/QUOTE]

Clean water and surface agitation.

[QUOTE][i]<a href=showthread.php?s=&postid=11496926#post11496926 target=_blank>Originally posted</a> by GSMguy [/i]
[B]Clean water and surface agitation. [/B][/QUOTE]

Arent those just shadows and not shimmer lines?

I run both halides and T5. I have clean water and plenty of surface agitation. I see some shadowing but not shimmer from the T5's.



[QUOTE][i]<a href=showthread.php?s=&postid=11494621#post11494621 target=_blank>Originally posted</a> by Txcowboy22 [/i]
[B]I was thinking about upgrading my lights and I was wondering what I should do? Could anyone tell me the main difference between the 2? I thought no other lighting could produce the natural colors like a halide and aren't they the brightest? [/B][/QUOTE]

I use MH for my main source, T5's for blue, and VHO's for actinic.

I have seen some incredible T5 only tanks, I however would use halides as my main source. I tryed out a T5 tank and prefer halides. It's more of a personal preference as long as you get proper lighting to the animal.

Yea the metal halides definitely produce much more caustics. It makes your tank seem like how it really is when snorkling or diving underwater. I'm upgrading my t5s to metal halides soon. Probably a combo though.

Whats an auto top off?

It's a device to automatically top off your tank or sump with freshwater to replace evaporation. You can go hi-tech or a simple DIY direction.

I am convinced with T5's. Can some one suggest me one that good for 5x2x2 (150gallons)? What bulbs and how to arrange the bulbs? thanks. Shin.

Talk to Greg at [url]http://www.reefgeek.com/[/url] . He's very knowledgable and will definitely steer you in the right direction. Sunlight Supply's Tek 5 fixtures and Retro Kits are the only way to go IMO.

I think both are great, and you can achieve the same outcome with both. So, like everyone has said I think it is all preference.

I also prefer halides for the shimmer. A fluorescent tube can never match halide shimmer physically. All the radiation from the bulb emanates isotropically from (essentially) a point source and when it strikes the surface of the water refracts, and as the surface of the water is in motion, the angles of refraction constantly change creating the shimmer.

As T5 emits radiation from a long tube, not a point source, the same can not be truly achieved.

That said both are great, I only prefer halide for aesthetic reasons.

[quote]T5s DO produce shimmer lines. I have T5s AND shimmer lines. [/quote]

The effect is not comparable.

So true. T5s wont generate as much caustics compared to metal halides at all. Doesnt do it any justice.

[QUOTE][i]<a href=showthread.php?s=&postid=11496957#post11496957 target=_blank>Originally posted</a> by tkeracer619 [/i]
[B]Arent those just shadows and not shimmer lines?
[/B][/QUOTE]

Same thing. Shimmer lines are 'shadows' caused by the refraction of the water surface. Like tiny little magnifying lenses across the surface of the water, there are great concentrations of light made in some areas, and shadows cast in other areas. The less of a 'point source' a light course is, the larger the wave has to be to produce the 'shimmer', or 'optical distortion. In a way, the 'shimmer' is a sign of a halide lights inferior penetration into water, as a light that is more of a point source than another will also diminish in intensity faster as per the inverse square law. But yes, for T5s, you can achieve 'shimmer', but it takes that much more surface agitation.

FWIW, since shimmer isnt always a good thing, the supplimental LED lighting systems that some EU mfg's like seaqualux put on their T5 systems are a very smart way to go. They give you the option of a more natural 'frequency' of 'shimmer' unlike halides by having the LED's programmed to go on and off along the length of the tank, similating the 'shimmer' of sunlight.