# t5 ho vs. pc



## epicfish (Sep 11, 2006)

Between those two, the PCs will give you more light.


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## evercl92 (Aug 15, 2006)

watt for watt, the hagen glo are far brighter than any CF I've seen. 

You're asking to decide between T5 HO and twice-the-wattage CF

Personally, I love the hagen glo setups, with Life Glo bulbs.


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## ruki (May 28, 2007)

Both will work.

I'm biased towards T5 HO since you can get more of the light they produce down into the aquarium. (it's the reflector and re-strike thing). Something like a TekLight fixture is difficult to beat. Light comes off the reflector at a high angle incident to the water surface so it penetrates pretty well. I have a TekLight, actually two of them. Watt for watt, it's tough to beat.

(More than a few vendors sell T5 HO fixtures where the tubes are too close together and don't put in a separate reflector for each tube. This is pretty much the same then as the typical PC fixture then in terms of wasting light.)

Some PC fixtures are pretty bad. I have one of the Coralife "Quad tube" 96 watt fixtures. The tube is thicker than most and with 3 bends with minimal gaps between the runs, more than half of the light is wasted with restrike. When you look at the angles involved, it's quite difficult for light bouncing of the reflector to actually go down into the tank. That what does comes on in at a low angle, so it doesn't penetrate very deeply since it's mostly bouncing off the glass.

My biases come in part from having 3 dozen tanks. My electricity bill is steep enough without wasting light. If it's just one tank or two, it's not going to matter as much


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## eggy (Jan 5, 2008)

i just got the pricing on the T5 HO GLO ballast from Hagen...and it is way cheaper than the Coralife E-Z. 

i may forget the individual refelectors and put that money towards a second T5HO ballast.

2X96w=192 watt pc
4x39w=156 watt t5

aaa-ha !

the replacement cost of T5 lamps are better than pc lamps & i have read that pc lamps don't last so long... so in the long run T5's may be the way to go.


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## ruki (May 28, 2007)

T5 and T5 HO are a standard originally adapted in Europe. All of these bulbs have the same shape, end contact pins and very similar characteristics that one can look up and make reasonable assumptions on.

Power Compact are customized to the point where you have many different shapes, different end contact points, and different characteristics (according to perhaps specious vendor claims on the package) that are vendor proprietary and difficult to look up and compare.

T5 and T5 HO are most efficient at 35 degrees C, which makes them a good fit for aquarium fixtures. T8 are most efficient at 25 degrees C. I haven't found information on what temperature is optimal for the various Power Compact tubes.

T5 HO has different numbers published on how long the tubes are supposed to last (at least 90 percent original brightness). Some say 2 years, some say 18 months.

I wouldn't skimp on reflectors though. That can multiply the light sent down into the tank by a factor of two compared to the typical shiny rectangular box reflector.

It's not really about many watts are consumed. It's how much light is sent down into the tank at something close to a 90 degree angle to the water's surface.

This preoccupation I see with raw watts consumed is something like saying that gallons per mile consumed is a desirable thing to maximize in a car.


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## Wooster (Jan 14, 2008)

Ok guys,

I am sure most of you are completely understanding everything up and above here. My problem is that it is all going WHOOOOOOOOOOOSH right over the top of my head. I have a 150 gall tank that is going to be fully planted. 6' in length (from one end to the other) x 2' in depth ( as in how deep the wat0er is) and 19" wide (as in back to front). So yes I need to know about lighting and yes I need to know which is best, but for the sake of those who are new to the lighting aspect of it all do you think we can try and make the replies understandable for those of us who have absolutely no knowledge what a lumen is or an H5 or PC lamp. Oh and by the way a PC to me is something I'm sending this on. 

Thanks in advance

Steve


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## neilfishguy (Dec 16, 2007)

Wooster said:


> Ok guys,
> 
> I am sure most of you are completely understanding everything up and above here. My problem is that it is all going WHOOOOOOOOOOOSH right over the top of my head. I have a 150 gall tank that is going to be fully planted. 6' in length (from one end to the other) x 2' in depth ( as in how deep the wat0er is) and 19" wide (as in back to front). So yes I need to know about lighting and yes I need to know which is best, but for the sake of those who are new to the lighting aspect of it all do you think we can try and make the replies understandable for those of us who have absolutely no knowledge what a lumen is or an H5 or PC lamp. Oh and by the way a PC to me is something I'm sending this on.
> 
> ...



The above post is technical by nature. We cant explain what everything is everytime we post about it!


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## tazcrash69 (Sep 27, 2005)

Wooster, First, if you have lighting questions, why not make your own post. It's bad form to hijack someone else's thread. 

Now, "best" is a very relative term, and next to impossible to answer. Do you know what your goal is? High light, high tech with CO2? Or low-light no CO2, low-maintanance? That will make a huge difference. 

As far as terminology, we have a great section with articles here:
http://www.plantedtank.net/articles.php


HTH


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## epicfish (Sep 11, 2006)

ruki's explanation is very thorough and if you glance at it briefly, it does seem to be very technical in nature. If I hadn't had any previous exposure to lighting, it would've confused me too.

Wooster: The link posted by Walter will get you on your way. Oh and yes, next time, please make a new post if you have questions of your own.


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## Wooster (Jan 14, 2008)

*Apologies all round*

Hi Guys ... my apologies if my post was not what it could have been. I did not intend to hijack the post and I will read up on the link posted by Walter.

Thanks for the heads up.

Steve


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## tazcrash69 (Sep 27, 2005)

NP Steve, It's a lot for someone who is unfamiliar with it all. 
Small bites, let it digest, it starts coming together. We were all newbies once.


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## ruki (May 28, 2007)

I'm all for being patient.

We've been victimized a bit by the lighting industry in how they market lighting products to us. It takes time to get past this to better understand how lighting products behave...

When I was young, my parents bought light bulbs in boxes that list the wattage in large print and the actual light output (measured in lumens) in very fine print. It seemed backwards to me even then.

But now I know it's backwards since with CF (Compact Fluorescent) also called PC (Power Compact) , they have the typical incandescent equivalent power usage in big print, the actual power usage in smaller print and the lumens listed in extra fine print. Is it any wonder that people get confused!

They were trying to do us a favor by dumbing things down for us. For example, it turns out that the lumen output of a bulb is not constant for the life of the bulb, it gets dimmer with time, so it was safer for them to just list the power consumption, and perhaps try to get customers to not notice that their bulbs get dimmer with time.  And that's just the beginning.

It takes time and thought to figure out what an optimal aquarium fixture is supposed to do and how poorly most available fixtures measure up to this.

Caveat emptor / Buyer beware.


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