T5-T8 and metal halide are the same

[Kevin8888]

Firstly I'm not trying to start a firestorm here, I just want some scientific proof that metal halides are better, because I don't know how many arguments I have read, but I just cannot accept that Metal Halides are better then Power Compacts, as I have not as of yet been able to locate any (actual) evidence showing a supiriority to Metal Halides.

I have done extencive internet searches, and have come up with the following data;

T12 is worse then the others so not included

T5 flourecent - produces 70-100 Lumens per watt, making its efficiency 10-15%

T8 flourecent (with electronic ballast) - produces 80-100 Lumens per watt, making its efficiency 12-15%

Metal halide - produces 65-115 Lumens per watt, making its efficiency 9.5-17%

YES Metal Halide CAN produce more, but its average is worse, so unless there is something at play other then lumens (such as wavelengths) then there is no reason why a T8 flourecent lighting with the same number of watts shouldn't be just as effective in a deep tank as a metal halide (yes you need more then one flourecent light to equal one metal halide). That combined with less heat produced by Flourecent, and the fact that they are half the cost of metal halides (both bulbs and fixtures) makes Flourecent superior to metal halides.

So the whole point of this post is to get someone to prove me wrong (scientificaly), or not, I don't care if I am wrong, I just don't want to invest hundreds of dollars extra in a setup that may not actualy be any better.

Of all the things I have read, there has been nothing but people working under the assumption that metal halides are better... just because everyone says they are... I want some actual proof, eather actual data from tests like lumens reaching the bottom of the tank or measurments of mulitple coral frags (from the same colony) grown under the different lights with the same other conditions.

So please any one with any data please come forward, again please don't just argue, because if I'm right it will save alot of people alot of money (except the Metal Halide companies lol) when they need to add lighting to their tanks.

 

[sostoudt]

well first i would recommend you to look at PAR(light plants can use for photosynthesis).
this varies drastically between bulbs, and even ballasts that drive the bulbs.

this will get you started for halide, http://www.manhattanreefs.com/lighting

im personally of the opinion there comparable, and the quality of the fixture you buy is more of a determining factor on which one is better.
beyond that i would decide based on what fits your tank better.

 

[Kevin8888]

hmm I forgot about PAR...(though that falls into the wavelenght catagory of my question) I guess i assumed similar wavelength emission. It seems you are also correct about the ballast quality thing, because I have already found one metal halide setup with as high as 50% efficiency, which doesn't change the fact that it has high amounts of the 500-400nm range wavelenght (opposite of the best for photosynthisis which is 500-700nm), but at the same time higher efficiency means more lumins per watt eather way. BUT there is no data on PC or other fluorescent lights.

 

[Kevin8888]

Ah but I found new data telling me that corals and inverts absorbe the 400-500nm range more easily (which when you think about it as water "looks" blue therefore more blue light makes it onto the corals and photosyntetic inverts.

 

[sostoudt]

when i said comparable i meant t5ho and halide.

i dont really want to touch on the wavelength issue beyond par, as different plants/corals have different needs

i believe you also need to consider the penetration depth through the water, its been so long since i looked up the info, but i think halide out preformed in this category(probably because of the high light from a single point, varies based on wattage of course), t5(HO?) came in second, power compact last.

i want to say t5 was good down to 20 inches.

i would also compare prices of replacement bulbs, over the lifespan of the fixture. i think PC is weak here

i wouldnt invest in PC or T8 bulbs, there older technology. There not designed made for growing things in general, but for energy efficiency for use in buildings.

if you want to see what generally puts out the best light, as it does vary based on quality like i said, go check you local tanning salon, they will probably use t5 and halide. t5 and halides have higher optimal operating temperatures, makes them more condusive to high lighting applications.

 

[sostoudt]

im trying to find the penetration data, which from my original source was a hobbyiest with a par meter. but im not having much luck.

but ive found several articles that state the fact MH penetrate farther, but no actual test data.

 

[Aeroxide]

Another thing to take into consideration is how the light is focused. There are parabolic reflectors available for T5 and metal halide bulbs that are able to focus all of the light captured from the bulb directly on the bottom of the tank. As far as I know, there aren't parabolic reflectors on the market for T8's. I have a T8 shop light on top of my 220g. Its cheap. There's a lot of light hitting the floor surrounding the tank and the wall behind the tank, because it isn't focused, so if I had to guess I'd say about half of the lumens are wasted on the floor and the wall, which isn't a problem for me because I'm not growing anything.

I remember reading on a reef website, that to design a parabola that would tightly focus all the light on the bottom of the tank, not letting any escape to the floor or wall, the reflector would have to be so large that you would only be able to fit 1 or 2 bulbs above the tank because of the width required. That is supposed to be due to the larger diameter of a T-8 or T-12 bulb.

 

[Kevin8888]

One thing I noticed on Sanjay's lighting guide was that 400W MH only had a 80 PPFD (the important number) increase frome the 190 PPFD at 250W so that is almost double the power but less then .5x increase in usefulness, so it would seem its better to have 2x250W and get double the output then to almost double and get a .5x increase.

I understand that the high intensity of the small source metal halides could penatrate further into the tank, but at the same time, I could have a larger number of flourecent for less money and less heat impact (but they take up more space), and I don't intend to contradict, but PC are not outdated tech, they are VHO flourecent though they do have a shortish lifespan (6-8 months?) I don't see why PC would do worse in penatration then T5s as they have more light emited per inch, but its possible that T5s are more advanced then PC. Its also very possible that T5s are better for aquarium use because of their smaller diameter but at the same time on a larger tank this could be unnessisary... even if T8s are better, which im not saying they are i have yet to find them used on a site that sells marine aquarium supplies, only found PC and T12s.

Again I accept that I could well be wrong, if I am big deal, I just want to make sure my hundreds of dollars dont go to waste lol, though its starting to look like metal halides are going to win sadly haha, so I'm also trying to find out if PC or T5s are better as they will be suplimenting my MH (assuming MH is better) because my tank plan is huge and its going to need alot of light. 1000 gallon, 4'x4'x8' or 3x'5'x8" or something along those lines, this is the biggest reason I'm asking as that is alot of MH something like 6-8 unless I can suppliment them with VHO flourecents. As I would rather buy 4ish and have 6-12 flourecent as supliments.

 

[Otto_VonBacon]

I want some actual proof, eather actual data from tests like lumens reaching the bottom of the tank or measurments of mulitple coral frags (from the same colony) grown under the different lights with the same other conditions.

That would actually be a pretty cool experiment to do just for the heck of it. It would be very expensive though. Unless you already had the stuff from previous tanks.

 

[Kevin8888]

That would actually be a pretty cool experiment to do just for the heck of it. It would be very expensive though. Unless you already had the stuff from previous tanks.

The other problem would be time haha, as it would have to be done at many different depths as well, as that effects performance too.