T 5 vs metal halide

[acroholic]

I don't believe metal halide lights make more heat than T5s. The heat from halides is concentrated in a much smaller area than T5s. A 250 watt halide bulb makes all its heat/light in an arc tube about 1.5" x .5". A single 48" 54 watt T5 bulb has a heat/light surface area approximately 30 times greater than a halide bulb. 250 watts of T5 lighting is almost five 4 foot tubes with about 150 times more heat/light emitting surface area than a single 250 watt halide bulb.

Concentrate all the heat emitted from five 54 watt T5 bulbs (20 feet) into an area 1.5" x .5" like it is in a single 250 watt halide bulb arc tube and see how hot it feels. The heat from T5s is just more spread out.
Dave

 

[grouper therapy]

Acroholic;393003 wrote: I don't believe metal halide lights make more heat than T5s. The heat from halides is concentrated in a much smaller area than T5s. A 250 watt halide bulb makes all its heat/light in an arc tube about 1.5" x .5". A single 48" 54 watt T5 bulb has a heat/light surface area approximately 30 times greater than a halide bulb. 250 watts of T5 lighting is almost five 4 foot tubes with about 150 times more heat/light emitting surface area than a single 250 watt halide bulb.

Concentrate all the heat emitted from five 54 watt T5 bulbs (20 feet) into an area 1.5" x .5" like it is in a single 250 watt halide bulb arc tube and see how hot it feels. The heat from T5s is just more spread out.
Dave

+1 250 watts is 250 watts How much of that is transferred to the water surface as heat is where the difference lies I woud think.

 

[snowmansnow]

no.. MH makes more heat.

With halides my temp was higher than with T5s.

T5s dont heat my tank over the day like halides did.. so it makes sense that they are cooler.... right?

b

 

[skriz]

MH is more economical than T5. With the new and improved reflectors, heat isn't really a factor anymore either. The only way t5's will come close to MH is by overdriving them. Once overdriven, they will produce a lot of heat which must be dealt with with fans.

I like the fact that you can manipulate the colour with t5. For me, you can't beat the shimmer of mh though.

If you're looking at par to watts ratio, mh is the best too. When it's time to change bulbs, you'll have fewer mh bulbs to change and less frequently.

If you're concerned about coral growth, water chemistry will have more of an effect than the lighting choice. You could SEE daily growth on my corals when I had my calcium reactor cranked up.

 

[snowmansnow]

another + to t5s in my book is that the light coverage is more complete. I remember with halides I could put softies off on the sides .. You can't get away from 4' lamps.

Minor I know, but just another reason why I personally like t5

 

[skriz]

SnowManSnow;393008 wrote: another + to t5s in my book is that the light coverage is more complete. I remember with halides I could put softies off on the sides .. You can't get away from 4' lamps.

Minor I know, but just another reason why I personally like t5

Then you just didn't have enough halides or the wrong reflectors.

 

[snowmansnow]

heres a link that compared T5 to 150 HQI.

I'm still looking for 250 comparision

 

[acroholic]

grouper therapy;393004 wrote: +1 250 watts is 250 watts How much of that is transferred to the water surface as heat is where the difference lies I woud think.

I think that is the difference. Halides may heat up the water more than T5s, but that doesn't mean they burn hotter, just transfer more heat to the water.

Matter of choice, but when it is stated that halides burn hotter than T5s, some folks just accept it as fact and repeat it and the myth gets perpetuated.
Dave

 

[william1]

I have ran both types of lights T5's and MH.

IMO......

PROS:

T5's are much less cooler.
Cost of electricty is 1/2 as much ar less.
Better color in coral.
Endless color combinations.

CONS:

Slower growing corals (SPS).
No shimmer:sad:

I like the T5 set up Im building with the Icecap 660 ballast. Overdriving the 8 bulbs should be great on my 180 gallon.

 

[snowmansnow]

Acroholic;393014 wrote: I think that is the difference. Halides may heat up the water more than T5s, but that doesn't mean they burn hotter, just transfer more heat to the water.

Matter of choice, but when it is stated that halides burn hotter than T5s, some folks just accept it as fact and repeat it and the myth gets perpetuated.
Dave

Not trying to argue .. just help me understand..

scene 1
MH setup over 120 G tank - 5-7 degree temp spike each day

scene 2
T5 setup over 120 G tank - 1-3 degree tamp spike each day

Which setup is runs cooler?

You state that the MH transfers more heat to the water.. but why? Isn't this just because they are HOTTER? I'm not thinking this is rocket science, but maybe I'm missing something.

 

[william1]

I believe Dave is right on the heat difference. Its nearly the same if you really want to compare it, but......... the acual heat difference it makes on the tank is different. Like Dave said its the MH concentrated light beam on the water that tends to heat the tank more than the T5's. I believe Cameron from this site had all T5's and one 70 watt MH added just for shimmer.

Its not that there hotter the reflectors beam the light down on the tank in one direct area, so the heat transfer is much greater.

 

[grouper therapy]

The heat from the bulbs either t5 or metal halide has to reach the surface of the water to heat it. To do that it has to transfer through air. If that heat is more concentrated more of it will obvisously reach the surface of the water before it is carried away by the air and dispersed. 250 watts is 250 watts if it isn't then we can throw the ohms law of electricity out the window.

 

[grouper therapy]

I read the link posted for the guy at reef central and his test is no where near an accurate comparison.

 

[snowmansnow]

The issue it that we are equating watts with heat. Watt isn't a measure of heat... Is it?

Are we assuming that 1 watt of electricity will create the same heat regardless of the source?

 

[snowmansnow]

What about 250 w led fixtures that produce almost NO heat?

 

[grouper therapy]

SnowManSnow;393032 wrote: What about 250 w led fixtures that produce almost NO heat?

They are not using 250 watts they are producing the same lumens as a 250 watt metal halide bulb. big difference.

 

[snowmansnow]

grouper therapy;393033 wrote: They are not using 250 watts they are producing the same lumens as a 250 watt metal halide bulb. big difference.

Fair

 

[grouper therapy]

SnowManSnow;393031 wrote: The issue it that we are equating watts with heat. Watt isn't a measure of heat... Is it?

Are we assuming that 1 watt of electricity will create the same heat regardless of the source?

Most all of your electric heaters are rated in watts.
1 Watt= 1Volt x 1Amp
So if your t-5 ballast are using the same 115 volts as your metal halides to burn their bulbs at the same wattage , no energy is saved in the production of light. There is usually some savings since less heat seems to be tranferred to the water in cooling the water.

 

[grouper therapy]

The issue it that we are equating watts with heat. Watt isn't a measure of heat... Is it?

Are we assuming that 1 watt of electricity will create the same heat regardless of the source?[/</em>quote]

Yes, in a resistive load, I am not sure about a inductive load(motors).

 

[gametrackers]

SnowManSnow;393012 wrote: heres a link that compared T5 to 150 HQI.

I'm still looking for 250 comparision

http://www.reefcentral.com/forums/showthread.php?threadid=1352234">http://www.reefcentral.com/forums/showthread.php?threadid=1352234</a>[/QUOTE]

I think this test is off by alot. There are a bunch of factors to consider.

#1 - There are only 300 watts of MH versus 432 watts of T5s. We already know that PC are not worth anything. I think bad comparison.

#2 - Go with 3 - 150 watt MHs versus the 8 - 54 watt T5s. Get the Par readings divide the watts by the par reading and you will end up with how many watts= one par.

#3 - How much area is covered? You take a 3 - 4' 54 watt T5 lamps, it spreads its power and heat over an larger area. The air movement will cool that area down faster than a 150 watt MH that is 8 inches and the power and heat is concetrate on a smaller area(depending on reflectors they vary coverage Which small are with the same heat exchange would heat up faster than a larger are with the same heat exchange. So you set up a tank that has 8 - 54 watt T5's and same one with 3 - 150 watts MH and the power and heat will be directed aproximatly over the same area versus putting 2 - 250 watt MH over the same tank.

#4 - Colors of bulbs are different from T5s to MH make a difference. More than like they would be hard to match up but enough to get close that the difference would be not much. ( I could be wrong here this is my opinion.)

#5 - Fixtures T5's and MH and HQI are diffrent and need to be purchase to fit your needs. I like some ares that have less coverage than others. I like a varity of corals. My light is more condensed in the center of the tank and my rock placement creates some shade areas.

#6 - Water Flow and Air movement helps with heat. I have a friend that put a MH fixture on a 55 tank recently and heat was getting to 82-83 I think. The fans in the fixture did not seem to move much air so he put a small fan blowing the air above the water and the Temp maintains 79 degrees. I have 65 cube that has 130 gallons of water moving through it and it never gets above 80 during the day but falls to 74 at night. I dont have a fan or heater on it. My house stays around 75 during the day.

If you shop for the right fixtures you can have great benifits with both type of equipment. It propably depends the trade off you want from one to the other. From what I have learned from this forum and seeing others equipment. I think T5s work great and will safely grow SPS and other corals and MH will grow SPS faster than T5's.

To answer the question that was asked personally I think either way would work for what you want just weigh the PROS and CONS not much either way.