What's the big deal with T5 lights?

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Aquarium Advice Apprentice
Feb 27, 2005
Boston, MA
So what's with them..? I see they cost a lot more! So what's the big deal? Less power, more light?

The are basicly the new kid on the block for reef lighting. I havent used them but my understanding is they run cooler than PC's and they are of course smaller in size than VHO's.

I belive the intensity may be even brighter than PC and VHO but I havnt seen any real scientific tests done to prove that.
Interesting... so from what I've seen, the pricing difference is about $300 - $400 bucks for the T5 lights.

Ex: (Both lights and prices are taken from MarineDepot.com)
Aqua Medic Ocean Light T5/MH Combo Series, 48" (2x250W + 2x54W) - Black $962.00
48" Current USA Outer Orbit 10000K HQI Metal Halide 2x150W Dual Daylight / 2x130W Dual Actinic & 6 Lunar Lights $643.90

For the difference in pricing, you could get a chiller. Then heat isn't an issue for just about anything you do. I guess I'd rather get the chiller (as I think I'm going to need one anyway) rather then spend extra money on the T5 lights that don't seem to be much of a benefit.

Thanks for the reply, FishFreek!
i have only been running my t-5 ligts for about a week now (still cycling). i bought the 6 x 54w teklight system from reefgeek. i know they are the newest thing on the market, but people who have them cannot say enough good things about them. i think the idea is that instead of using metal halides, the t-5 offer a cheaper alternative (not condoning this). you also have to be careful with the kind of reflector that comes with the t-5 lights. the parabolic reflectors that come with tek lights reflect very close to 100% of the light back into the tank, which is why you can have more success with lower w/gal. someone from another forum has been running tek lights for almost a year now, and is successfully keeping clams and sps with only 2.8w/gal. he is using 4 x 39w in a 55 gal tank and has some beautiful sequential pictures to back the lights up. i was also thinking about going metal halide, but did not want the higher cost of electricity, or the heat situation. not saying this is the right way, just the way i decided to go. i will report back on the tek light system in a few months hopefull with some pictures.
Those two setups I would not consiter to be equivlent. They are more like apples and oranges. One uses a pair of 250W MH bulbs where as the other is 150W MH bulbs. That in itself will make up for some of the difference. Another difference is that it appears they are both different brands so that will also affect price.

I suspect if you compaired equivlent lighting setups the differances in price will be less.
In theory no. Watt is a measure of power consumption so a 250W of electricyis a 250W of electricty regarless of what type of bulb. With that said though a 250W MH bulb will be much more intense than 250W of PC lighting over a 2' square area. Outside that 2' area the PC bulbs will be more intense. This is becaues MH bulbs is a single point of light and as you get further away from the light source the intensity drops off. With florecent bulbs the light source is the entire bulb so the intensity is spread out over the entire lengh of the bulb.
OK, that makes sense.

I have never been able to figure out why people say that MH bulbs are more expensive to run. 250w is 250w is 250w in my book - whether it be PC, MH, or a toaster oven for that matter.
There are 2 main types of lighting: high intensity discharge(HID) and the fluorescent(VHO,PC,T5).

Equivalent wattage fixtures: 250wt HID vs 250wt Fluro
1) will consume the same amount of electricity
2) HID will penetrate much deeper into the tank
3) fluro wins the battle for evenly dispersed light throughout the tank
4) they will both put out a good amount of heat

Now, I haven't had time to fine tune the maths, but replacing bulbs also becomes a factor:

Six 40 watt PC 50/50 bulbs = $120
One 250 watt 14k MH = $57
(prices from Captivereefs)

Tosum it up, it all depends on your tank parameters (size/depth). Ideally a mix of both types should be sought nice dawn to dusk effect). Many people will tell you that you can't have this or that in your tank unless you have MH (not true -- have seen some incredible tanks using only fluro lighting).

As for the most bang for your buck (PC vs T5 vs VHO), I don't really have answer.

I'm guessing that T5 wins out with regards to:
1. light output per watt
2. more balanced PAR spectrum
3. unobtrussiveness of bulb/fitting

I may be misled on some of this (am by no means an expert), please let me know


I am running 4x54 watts T5's in my 100gallon, I didnt think it was going to be enough, my tank is bright as heck, if you have the money for MH i would recommend them, but for me these lights work great.
Can you run T5 directly on-top of your tank? i.e. don't have to hang them from the ceiling or use legs?

I have my Coralife 96x2 PC sitting directly on the glass top. Could one run a T5 hood/fixture this same way?
I have the same thing as MoeJoePHD... only on a 75g. I got the CoralVue 4x54w retro kit from Darin at CaptiveReefs (a big saving of money - 225 vs 500+) and I thought these things were bright as ever!! Even people comment on how bright they are.... the colors are really nice with my 2x10k 2x03 actinics... clear white light. BUT, in the past few days I have had a scare and was on a Metal Halide additon hunt because I had two true percs and they had been doing fine for the few days I had them... went out and got a green bubble tip anemone. All was fine that evening and into the wee-hours of the morning and then the next evening - WHAM.. he was super shriveled and bright green and oozing and losing body parts...pull him gradually off the overflow and he was dead :( 40.00 down the drain and my lfs says "tough". (never going back to those arses btw) I even asked if I could just have 10.00 off of another later - but nooooo. Anyways... at first I thought it was the lack if light and then I look at my water temp which had been a consisten 80 for weeks and it was 76.8!!!! I realized my heater had came unpugged when fiddling with stuff! It seemed my fish were not as active (still lively though) and a few sponges that came with my lr looked weak. Everything seems well though now. SO, I don't know if it was my lighting or the low temp :( Sorry for all the rambling - though I would give my complete experience with life/t5's so far :)
ohh and... these things put off NO heat... its rediculous. I put my hand all over my reflector... barely feels warm. I NEVER feel warmth on top of my tank. I can even leave my hands on the bulbs for the longest time. So, heat is not a factor with t-5... I mean none at all! hth :)
Yea Aspec you can just put em on top of the tank thats how mine is set up intill i get my canopy all built, Like I said I am all for T5s, I also have 210k's and 2 03's, looks sweet!!
There are a lot of ways to do this reef thing and you can definitely have success with t5's, pc's and mh's. While one kind of lighting may have a benefit that the others don’t have, they are all usable and sometimes you just have to make a decision. I have what I think is a reasonably fine 120 gallon reef that I've run with 520 watts of power compacts for a year now:



Still, I just bought a new fixture with two 250 watt mh’s and t5 actinic support so I could get some coral for the lower part of the rock. Under the pc’s, I had to have the corals toward the top of the rock because I found that the lighting didn’t penetrate down toward the bottom. (On the other hand, mine’s 24 inches deep and if it were shallower, say 18 inches, the pc’s would have been perfectly fine lower down on the rock. If I couldn’t afford the new lighting fixture, I would have been perfectly happy with the pc’s. By the way, I haven’t replaced any of the bulbs since I put them on the tank a year ago and I see no reduction in brightness, intensity, no algae blooms and no affects on the health of the corals in the tank.)

I could gotten a new t5 unit, which I hear very good things about, instead of the mh/t5 combo. But just researching which new lighting to buy was utterly confusing and I finally just had to make a decision, so I opted for the one that I bought because of heat issues that I felt were best resolved with my choice.
If you price MH/T-5 units, as fishfreek said, and compare them to MH/VHO or MH/PC of equivalent wattage, the T-5's are very competitive. T-5 bulbs are more intense than VHO or PC. As for power usage, the bulb itself will use the wattage it's rated for, but that doesn't mean the ballast will only draw that much. Energy is heat...if your core/coil MH ballast runs hot enough to cook your breakfast on, you can bet it's pulling more than the amount needed to light the bulb. Whether it's a significant difference or not, I'm not sure. You can get a 48" 2x250w MH with T-5 actinics for around $725.00.
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