# Metal Halide Effiency



## Plaid (Nov 10, 2008)

Hello, everyone. I've got a question about dem Metal Halides. I want a high-tech, high-light tank, which is a 25 gallon cube. 1.5 foot on each side.

I know high light on a tank like this would be, like, 50-75 watts of T5HO lighting.
So, my question is, is a 70-watt Metal Halide pendant as good, or better, than a 70-ish watt fluorescent fixture?

Thanks again,
Wes


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## Ciddian (Mar 15, 2006)

I... am not going to pretend that I know what I am talking about regarding lights but the one cool thing about the MH is that awesome shimmer effect they give off. :3

Hopefully someone else who knows more than me can chime in. lol


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## Plaid (Nov 10, 2008)

Eugh. Thanks, Cid. : P

I know my compact fluorescent, I know my T8s, T5s, for fresh water plants only.

But when at the age of 18, I'm falling behind the newfangled technology of LED strips and Metal Halide death rays, things are moving too fast. 

Anyone (Darkblade.) know the answer to the metal halide thing?


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## UnderTheSea (Jun 2, 2008)

You can find many opinions and a few techie analysis of a comparison of T5HO to MH.

In both cases the three major components play a factor in the efficiency and quality of the light. Ballast, Reflector and Bulb. Do you home work on each of the three for MH and T5HO.

As Cid did say, many like the shimmer effect of the MH. We do know several individuals that have gone from MH to T5HO and have switched back just because of the shimmer.

If you need any assistance finding specs and info on each let us know and we will assist.


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## Plaid (Nov 10, 2008)

Maybe I should rephrase my question. I know the ballast is good, the reflector is also above average. The bulb is weak, but will be replaced.

IS a 70 Watt HQI Pendant high light on a 25 gallon tank? I'm thinking that it is, but I want someone to tell me "Yep. A good spectrum Metal Halide light is enough for a planted tank, at three watts per gallon."

Thanks all for your help so far.
Wes

PS: Looking at efficiency, the MH is gives off more lumens per watt than tubes. I think the fixture will work.


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## Darkblade48 (Jan 28, 2008)

Yes, a 70 watt MH will give you high light over your cube. Of course, it is also dependent on how high you hang it above your tank.

Be careful of starting an algae farm.


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## Plaid (Nov 10, 2008)

Alright! Just what I was looking to hear.

I'll be running pressurised CO2, and dosing EI.

If algae becomes an issue, I'll just raise the light another three inches, until things balance.

Thanks, everyone!
Wes


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## Chris S (Dec 19, 2007)

If it were me, I would be aiming for T5 HO's.

I guess it might just be personal preference, but in my experience MH's just aren't necessary for a planted tank.

The bulbs are a pain in the ass: expensive and lose a lot of efficiency throughout their lifespan. This for me is a big no-no, especially with a high-tech planted tank that will rely so heavily on a balance.

The heat is a pain in the ass, but if you are using it as a pendant, I guess this does not apply.

I also like being able to turn lights on and off as I wish, which you can't really do with MH's.

Also, while being a smaller MH unit, it still sucks a lot more power.

Unless you have already bought the MH's, I don't think there is any reason to use them over T5HO's. I can only find reasons not to use them.

Just my two cents though.


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## Plaid (Nov 10, 2008)

Maybe it's best I go for for the T5's.

I WOULD like that sunlight shimmer, but I can deal without it. I'll save the metal halides for a big tank, some day. My SUPER masterpiece. This masterpiece will be my prototype.

And maybe I'm struggling with the effieciency thing. Does a 70 Watt metal halide use more energy than 70 watts of T5?

And expensive bulbs is never a good thing.

Many thanks to Cris S for helping me decide on this one. I'll go for the T5s, it seems like a better option for now.

Can you recommend a nice, bright fixture for an 18-inch tank?

Wes


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## bae (May 11, 2007)

Plaid said:


> And maybe I'm struggling with the effieciency thing. Does a 70 Watt metal halide use more energy than 70 watts of T5?


They both use about 70 watts of energy, but the MH puts out more heat and less light than the T5.


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## Chris S (Dec 19, 2007)

As bae says, 70 watts is 70 watts. It is just the amount of power going into the fixture. 

I wouldn't want to use a 70watt t5ho on a 29 g tank though, I would think it was overkill.


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## wtac (Mar 17, 2006)

I also prefer T5HO vs MH for FW planted. One thing you have to consider is that the heat generated by MH's as they will "burn"/dry out leaves as they start to grow out of the water. Not very pleasing to the eye if that's the overall look you are trying to acheive.

As others have mentioned watts used is watts used. How the energy is converted into usable light is one thing, the heat generated is "wasted" energy is another.

Longterm (total cost of ownership), T5HO is the better performer (energy used for light emission and even coverage over the aquarium) and bulb replacement (annually for MH vs 1.5-2yrs T5HO). Also you have more flexibility as one can change bulbs (higher or lower K value) to get the desired look. Assuming the cube is of a std length (24"), bulbs range from $15-30. [email protected] are a little more difficult to find in the 6500-10,000K range and if you don't like the color you are looking @~$45-100/bulb.

JM2C


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## Plaid (Nov 10, 2008)

Wow, I'm very pleased with the information available to a member of this forum, should he just ask.

I've made up my mind on the lighting, I'm gonna go with the T5HOs. I'm looking at a few different ones, and I was wondering what you all think of the following:

AHSupply 2x36 kit - http://www.ahsupply.com/36-55w.htm
Roughly 100 CAD, shipped to my door.

And... well... that looks like my only real choice, other than the halides...
Unless you all can offer an idea?

Thanks!
Wes


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## Chris S (Dec 19, 2007)

Check what your local pet shop and hydroponic shops have to offer.

I'm not sure what would work well with a 25 cube to be honest.


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## wtac (Mar 17, 2006)

Honestly, I'm not a fan of PC lighting. Replacement cost and frequency are the biggest negatives. On the CDN market, as one doesn't want to be out too long w/o light, you are looking at ~$40-60/bulb every 9-12months, if you are looking at max light output an minimal spectral shift. The latter point isn't as important for FW planted as it is for coral systems.

Another negative to PC's is the bulb shape. There is more restrike (light emitted from the bulb hitting the adjacent tube) vs just a single tube running along the reflector.

T5HO lighting systems cost more than PC's but you will save on bulb replacement cost and frequency. A plus T5HO is the color temp available.


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## Plaid (Nov 10, 2008)

Hm. So T5HO are just cheaper, by nature.

A 25 cube is only 18 inches deep, 16-ish with substrate. So it's not THAT deep, my 50 is the same and I've had no trouble lighting it.

Any recommendations for a 18-ish inch T5HO fixture? Anyone?


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## TBemba (Jan 11, 2010)

Would these lights not be any good?

Or would this one be better?


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## Plaid (Nov 10, 2008)

Sorry, TBemba, but those seem horrifyingly bright. Even half that power would start an algae war in a 25 gallon tank.
I do appreciate you looking for me, though! But as we've been discussing early in the thread, metal halides are not what I'm after, right now.

Thanks anyway,
Wes


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