View Full Version : Why T5's over Metal Halides?

09/27/2007, 12:23 AM
I have never personally used T5's but it seems to be a very popular choice of lights for a lot of people on this board. The only pro of using T5's over MH's that I am aware of is the heat issue and maybe electrical costs. Can some T5 owners chime in on this? Why did you pick T5's over MH's?

09/27/2007, 12:40 AM
Allot less heat means no skimmer for me.

09/27/2007, 01:02 AM
"Allot" less heat = no skimmer? that's really odd...

Jimmy, I think it also produces a more even spread since there are much more lamps, thus the edges of your tank get a good amount of light as well. The profile of the fixture is also much thinner.

I don't know about heat and power, I mean if you end up with more wattage going through it to compete with PAR of MH, then you'd be using more... but I think that depends on quality of lamp + reflector.

Going for high end T5 fixtures would be the only way it's worth it... otherwise I think the MH + T5 combo still does better.

T5HO is still freakin hot...

But that's just my take from sort of giving these kind of threads a once over.

The cons I hear are you lose that "shimmer" from metal halides... though you still get good color etc, something's missing? I've personally had no experience with T5's, but that's what I hear.

09/27/2007, 02:19 AM
Ive done both T5 and MH.

Had the PFO 2x250w DE MH 2x110w VHO fixture. Then my next tank got what you see in my icon. 4x54w HO T5 overdriven by IC 660 and 2x54w HO T5 for dusk/dawn effect.

I think they both have there benefits but I prefer the look of MH lighting. Without the shimmer, it just doesn't look as natural to me. So with my new setup, I'm going with both MH and T5's.

09/27/2007, 03:25 AM
<a href=showthread.php?s=&postid=10852165#post10852165 target=_blank>Originally posted</a> by sd_schoppert
Allot less heat means no skimmer for me.
Are you sure you don't mean chiller?

One can usually survive with metal halides and a fan blowing aver the surface of the tank without needing a chiller.

09/27/2007, 06:46 AM
T-5's don't heat up the water as much, the fixture gets hot but not the water like MH. I have t-5 on one tank and MH on the other, the canopy is able to be shorter with T-5. The MH does give the shimmer though. Hard to say which I like best here. My next upgrade will be LED lights though!

09/27/2007, 07:42 AM
The heat is the same, the t5's emit heat spreadout unlike the MH being a point source light. Both can be controlled by fans. I personally like the t5's better because they seem to light the tank better as far as covering every corner. There's alot of options as well. But you don't get the skimmer affect with them, which imo is very overated.

09/27/2007, 08:42 AM
you can get a better color combination out of t5's and re-arrange them how you like them. the par is spread out more over the width of the bulb vs the halide. halides produce more par directly under the bulb and it reduces as the distance is greater from the center. i flip flopped for a long time and finally went t5. am happy with them, but am looking to upgrade to a better t5 fixture now. if you t5, just make sure you do it right the first time - you'll be happier.

09/27/2007, 12:07 PM
i think people mean to type "shimmer" when they say "skimmer" =P spell check!

09/27/2007, 12:11 PM
lol, correct! ; ) Nothin like that darn skimmer affect!

09/27/2007, 12:34 PM
Pro- Longer between bulb changes, no big hit to the wallet with being able to change 1 bulb at a time, less heat, easy to upgrade(Retro), easy to modify color with different bulb choices.
Con- no shimmer

09/27/2007, 05:45 PM
I use both, heat is not a big issue if you keep the MH 12" from the water. And I also keep the T5s about 8" from the water. Water stays at 80 with controller and fans. NO Chiller!!

09/27/2007, 06:24 PM
Well i used T5's Because i was told that they are just about as good as MH.
The other reason was because of cost of the light and hydro bill.

09/27/2007, 06:34 PM
I would agree, they can be pretty equiv. and cost is always a good reason.

09/27/2007, 06:41 PM
I used t5s for years before switching to MH. The only advantage of t5s over just MH is the even spread of light over the tank and dusk/dawn effect.

09/27/2007, 06:51 PM
Yeah, i have 3 MH that run 8 hrs a day, and 4 T5s that run 12 hrs. They give me that dawn/dusk simulation, and they also give me the color i like. I run 10k bulbs for the MHs, and the T5's are actinic, i like the overall appearance with both. You get shimmer with MH, and a more even spread of light with the T5's.

09/27/2007, 06:52 PM
thanks for chiming everyone.....I would not be able to sacrifice the "shimmer" effect that MH's produces. I feel it gives a reef tank a nice natural look. I'm going to pick up a T5 and MH combo and get the best of both worlds.

09/27/2007, 07:22 PM
Ok, which company makes a particularly good T5/MH Combo? Consider coverage for a 150 tall (48 x 24 x 30)

09/27/2007, 08:11 PM
sunlight supply makes a good one. Called the maristar...the maristar 2 should be out by now.

09/27/2007, 08:46 PM
maristar 2? any info on that one?

i'm probably going to get a Aquactinics MH/T5 with the 15K iwasaki lamps

09/27/2007, 08:49 PM
It comes with 250watt DE MH and 4x t5s.

Not sure when its coming out....

09/27/2007, 10:49 PM
<a href=showthread.php?s=&postid=10858063#post10858063 target=_blank>Originally posted</a> by SpareParts
Ok, which company makes a particularly good T5/MH Combo? Consider coverage for a 150 tall (48 x 24 x 30)

wow same tank as mine. im using 250 watt retro fit.

09/28/2007, 12:07 AM
Ugh... another T5 vs. Halide thread... thats not really the point though guys. FWIW, halides are the most efficient light as far as output per watt until you start to get on the bluer side of the spectrum. T5s dont see this drop in output... one of the highest output T5s is the ATI blue+ bulb... which makes a bright blue light... without alot of daylight like a 20,000K halide.

There are some myths that need to be disposed of though...

T5s dont make less heat, in fact, they most likely make more per watt than halides. The perception is that they are cooler because they are cooler to the touch... well... thats because they have 40x the surface area than a halide of the same wattage to shed that heat across! In the end, T5s can actually be worse because they cover more of the surface of the tank... while halides might heat a 'patch' over a tank, and leave the rest open to cool. With both, what is most important is what you do with the heat. Halides, pendants usually, dont have any built in means of cooling, and a couple fans in a canopy dont direct the flow as efficiently as a ducted fixture with a dedicated fan (like a lumenarc 3 with ducts). Most T5s, since phosphor based lights are sensitive to their own heat (this goes for LED's as well which actually make more heat than any other light source per watt... they are just better at directing that heat away), happen to have built in cooling, which in turn often ends up helping the tank cool. But if you are intending to switch from halides to T5s just to reduce heat... well... the only way that really makes sense is if you end up using less watts.

You can see more on T5s vs. Halides in this thread...

What it really comes down to is the tank in particular, IMO. Some tanks are just better suited to T5s, some better to Halides. A 48x12x24" tall tank (close to a 55g) lends itself better to being lit with 4-6 rows of T5s for a total wattage of 216-324 watts. A 24x24x24" tank (same volume) lends itself better to a single halide pendant.

The 55g-ish tank, if lit with halides, is tall enough to require dual 250's. One isnt enough because its a 4' tank. Then, those halides will be 8-12" above the tank, bleeding most of their light out the front and back anyways... but if you lowered the pendants and used 150's, you wouldnt get good coverage. Anyways... its a big waste. A 55g is a poster-child for T5s. Being close to the water, and long, you can light a 55g and get more light with T5s for less wattage. Its a tall tank as well, which is good because watt for watt, T5s penetrate deeper than halides... as in, the light gradient isnt as drastic as with halides. This can be a good thing, and a bad thing. In the wild, corals can grow 2' before they see the light change that we see i just 2" of height. The downside is, whatever light level you have at the top of the tank, you are going to have alot of at the bottom. Halides are more focused up at the top, like a spotlight. You get PAR values and hot spots that can be just plain too much for many corals. T5s are spread out more at the top. Halides dont penetrate into the water as well, not unless you use lumenarcs (making the halide less of a point source by spreading it out). You can have a halide with a PAR of 700 at the top and 150 at the sand, and T5s with a larger area of 450 PAR at the top, and 200 at the sand.

As for a 60g cube (24" cube), a halide is just better. You cant pack enough T5s into a 2'x2' area (8 at most really of the 24watters) to light a 60g (thats under 200watts). And T5s arent as cost effective at 2' as they are at 4'. The cost in sizing T5s is not in the length of the bulbs... a 4' bulb costs maybe $20 and the 2' one costs $19. You can buy a 4bulb, 4' fixture for less than a 6 bulb, 2' fixture. The cost of an extra foot of glass and phosphors is nothing... the cost of extra endcaps, ballasts, etc... thats where its at. On a 4' tank, T5s are very cost effective. On a 3'... you are still ahead often. On a 2' tank... its not so good. For nano's, like a 20H or somehting, T5s are still a good option because you are only using 2-4 bulbs.... but an 8x24watt setup would be silly. A single halide would light a 60g cube better. The bulb replacement costs alone on the t5s would be about $80-120 per year, and the replacement cost on a single halide... $65-70? And the single halide can get more light into the tank.

It really comes down to the tank, the light field you are trying to create in the tank, and the color.

If you like blue, like 20,000Ks, you might want to consider T5s more than normal. Lets face it, a 10,000K halide is near impossible to beat by any other technology... but as you go bluer, that output can get cut in half, or even 1/3. Ouch. T5s dont see that kind of drop as they go bluer.

And the last thing I do like about T5s more than halides is the mix & match scenario. If you are using 2x250watt halides over a tank... thats it. If you want to change the color, you need to change the whole bulb... and often this means a drastic change... not just a 'little bit bluer' or 'a bit more daylight'. In fact, if you like blue halides, and you want just a bit more daylight for a less monochromatic blue look... it doesnt even exist. With T5s, you can mix and match bulbs to get just the right spectrum. Want more daylight? Fine, pull one of the aquablue (an actinic day/11,000Kish bulb) and put a midday (a 6500-5000K bulb) in. The other blue and actinics will still be there, so you can take smaller steps, and blend the bulbs with each other. You can combine daylight bulbs with blue bulbs, and have a killer output and spectrum for all corals red through blue with one system. Thats not as easily done with halides.

If your tank is large enough, by all means, use both... but I know... its hard to cram halides in decent reflectors in with anything more than 2 rows of T5s, let alone do it cost effectively. 75g tanks can do dual halides w/ 2-4 strips of T5s... but its $$$. On 120g tanks on up though, its easier to do, and actually a very good combo.

The following are tanks that I would consider more T5 friendly....

Honestly, for most tanks less than 75g I would say T5s are a better route (except a 60g cube or some other 'cube' or hex tank). You loose the shimmer, but so what.

FWIW, when I did my 40B 'side by side' evaluation, I made everything between the three 40B's I was running the same... I even linked the water. I matched the spectrums of the bulbs as well as wattage (you can see in the MH vs. T5 thread), and in the end, there is just something about the T5s that made corals 'pop' more than the halide, even with the EVC 20,000K in there. I have never seen an orange whorling cap turn neon blood red before. I could never get it to look like that under halides. Same for some other corals. Zoas, GSP, LPS... they all pretty much color in the same no matter what. Same with most milliporas/prostratas... but purple bonsai, red bonsai, suharsonoi, tenuis, aspera, valida, etc... I have never seen then get as intense as under the T5s... even under lower lighting. I have a pink w/ light blue tip prostrata that NEEDS at least PAR levels in the 450 range to keep its color if under halides. Leave it in light under 250, and it just packs up and dies. Under the T5s, I had it at a point in the tank that was about 300-350, and it turned the sickest pink/blue color. I cant get that with halide... I just cant.

09/28/2007, 06:34 AM
that was a well though out post and held a lot of info ...thanks

09/28/2007, 12:36 PM
Yes great information hahnmeister. I'm building a 75 right now and had picked up a dual 175mh setup and was going to run 14k Iwasaki's but was kicking around the idea of also adding a 4x54 T5HO setup with it to give me the ability to add or change the color a little.