# T8/T12



## DLeDeaux (Dec 27, 2002)

I believe all of the T8 and T12 stuff is interchangeable. I don't recall seeing any different products for the different bulbs.

As for the HO systems, if your T8/T12 systems are meeting your requirements for lighting, then there is no need for HO systems. One of the reasons people opt for those systems is when the amount of space required for lighting exceeds the amount of tank "real estate".

Of course there are many other reasons people choose HO lighting.


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## Wasserpest (Jun 12, 2003)

John,

T8 and T12 are somewhat interchangeable, with the difference that you get the best results from T8's when using them with electronic ballasts, while T12 bulbs don't work with electronic ballasts (or so I read).
T8's with electronic ballasts are more efficient, giving you more lumens per watt compared to T12 bulbs.

Compact HO? Do you mean PC (power compact) lights? They allow you to get more light into your tank, which costs more money and creates more heat.


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## GDominy (Jul 30, 2002)

I'm using T12's with electronic ballasts so thats not the reason...

T8's are more efficient in a number of ways..

1.) Bulb shape. With a smaller diameter bulb there is a high concentration of light at the source with less restrike (smaller surface area to block the light)

2.) Energy consumption. T8's use less energy to produce a higher volume of light, this is not a function of the ballast.

Compact Flourescent bulbs take this one step further.. in fact all they are is a T5 tube that has been bent into a "U" shape. Once again, the lower the "T" rating, the smaller the bulb, and the more efficient...

T5's have not taken North America by storm yet, but in Europe they are all the rage. Linear T5's ar e a much better design then the Compact Flourescent tubes weve been accostomed to over here.


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## JF (Oct 29, 2003)

I have eletronic balasts. Now I read about supercharegin these lights to put more power through them. Any opinions on this?


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## Scorpion (Oct 10, 2003)

JF said:


> I have eletronic balasts. Now I read about supercharegin these lights to put more power through them. Any opinions on this?


If you mean overdriving them, just wait for Sam aka Gulf Coast Aquarium to read this post. That dude is a genius when it comes to overdriving bulbs


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## GulfCoastAquarian (Jul 30, 2002)

Uhhh, I don't know about Robert's assessment, but maybe I've spent just a little more time than is normal, tinkering with these electronic ballasts. 
As Gareth said, T12's can be used with electronic ballasts. What Wasserpest read was that there aren't any electronic ballasts designed for T12's (that I know of). The only e-ballasts around are for F32T8's. But you'd be amazed at how you can use these ballasts to drive just about any fluorescent tube.

To get an idea of what you might be able to do as far as overdriving your bulbs, lets take inventory of what you've got. Read the description on the 2 ballasts you've got.

As a note: the average F32T8 bulb doesn't generally produce more lux than the average F40T12 bulb. Yes, they are more efficient, but that simply means that for a given amount of electricity, they produce more light. The F40T12 draws ~25% more electricity, but only produces slightly more light, given the same phosphor balance and spectral output.


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## JF (Oct 29, 2003)

I'll jot the datea when I go home later. One ballast (yet to be used, came with a Coralife set) the other is a replacement as I burned out the Coralife, as one can nay balast by revering the pins for the bulbs. I purchased a good, $35, ballast) Numbers forthcomming.

Now that I am focusing on using what I have. how about reflectors. When I was going to buy the complete unit this was included. my old box will be replaced and (out side of this site) internet research has indicated that mirrored plexiglass is the best though it does not angle like metal. What say y'all?


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## Kinketsu (Oct 23, 2003)

GulfCoastAquarian said:


> As a note: the average F32T8 bulb doesn't generally produce more lux than the average F40T12 bulb. Yes, they are more efficient, but that simply means that for a given amount of electricity, they produce more light. The F40T12 draws ~25% more electricity, but only produces slightly more light, given the same phosphor balance and spectral output.


A question about this: I have seen a couple of posts suggesting that "a fluorescent watt is a fluorescent watt". So, for instance, suppose you had a 4-ft long 65g. To put about 2 W/g over that, you could use 3 T12 @ 40W or 4 T8 @ 32W. 

But is W/g the right measure? By what you've said those two scenarios are actually quite a bit different in terms of lux (with T8 winning). Doesn't then the T8 produce more usable light for the same number of watts? Wouldn't that in turn imply watts/gallon is not quite the right thing? 

(I realize watts/gallon a generalization in any case. But I'm wondering if there some fundamental definition I've got mixed up ... Such as: lux is what matters to people, but what matters to plants might not be visible to us, and all the watts are accounted for in that.)

I'd love to hear an answer to this ... it's been confusing the heck out of me. Sorry if my question itself is confusing ... I hope it makes enough sense that you know what I'm asking.

Thanks,
Kinketsu


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## Wasserpest (Jun 12, 2003)

Light efficiency is measured in lumen/watt, the higher this number, the more efficient a light source. Since the lumens/watt in a T8 are usually higher than in a T12, in your scenario, the 4 T8s would create more light than the 3 T12s. 

But... the light output also varies depending on the spectrum. Now it gets really complicated, going into photosynthetic active radiation, and why a lamp with less light output actually gets to grow plants better.

Lux is the light falling onto a surface, so this will change a lot depending on your reflectors, and a little bit if you are using glass covers or not. Of course this is in the end what matters, but it is easier to deal with watts or lumens (which is written on bulb or packaging) than measuring luxes. As you can see, Lux is somewhat independent from the type of lamp.

That's my take on it anyway... leading to my conclusion that using T8's usually better than T12s, but then there are better spectrum lamps available for T12s, etc etc I will shut up now. :mrgreen:


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## Kinketsu (Oct 23, 2003)

I found the following on AH Supply website this morning, which confirms one of my suspicions about all this:

"A *lumen* is essentially a measurement of brightness to the human eye and is therefore very heavily weighted to the middle wavelengths of light that the human eye responds to most readily. As such, this measurement is not very helpful for aquarium applications since the middle wavelengths are the least important to aquarium inhabitants. To focus on lumens can be very misleading."

Still, that doesn't to me answer the question whether a fluorescent watt from a T12 is equivalent to a fluorescent watt from a T8, as well obviously as tons of questions about colour temperature, spectrum, etc.

I guess it's just complicated. I'll experiment and maybe learn, I guess.

Cheers,
Kinketsu


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## GulfCoastAquarian (Jul 30, 2002)

Wasserpest is right. The watts per gallon rule is very general. It was created by taking the more accurate lumens per square meter rule and applying it to a more easily understandable rule assuming the use of Normal Output Fluorescent tubes over a typical display tank with fairly tall dimensions. 
This article shows a survey done a few years back showing typical lighting intensities used on planted tanks of varying sizes. It doesn't take into account the relative efficiency of each type of lighting used (metal Halide, NO Fluorescent, PC Fluorescent, etc.), though.

Even lumens isn't a good measure to judge adequate lighting intensity for plants since it takes into account the human visible spectrum, not the Photosynthetic Active Spectrum. 

Ultimatley, let the plants be the judge. If you feel you've maximized growth with your current lighting, and you arent' satisfied, then increase the wattage.


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## Anonymous (Mar 2, 2003)

When buying or making a lighting system, several other factors not mentioned should be taken into account. First, what does the lighting system look like on top of your tank? If you DIY, will it be something you are pleased with? If not, then a retrofit or a custom job might be the way to go. Second, are you able to DIY wire and be worry free once you are done? If not, a custom job or premade may be the way to go. Finally, if you DIY, do you have the option to fit a good type of reflector inside the hood? Adding a good AH Supply reflector or reflective mylar to a DIY or premade hood makes a world of difference--you dont want light spilling out all over your room and not going into the tank.
All and all, I have a double 2XODNO hood on my 55 g for a little over 200w. If I had to do it again, I would but a kit from AH Supply and built one out of PCs. Im very interested in T-5s, but sadly not even Home Depot carries any Plant and Aquarium type T-8s (48 inch) where I live.


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## JF (Oct 29, 2003)

so this is the data:

A Proline eletronic ballast. 120 volts/60 Hz. designed for 2 F40T12 rapid start bulbs. .64 amps used for 2 F40T12. It also says 650 volts open circuit. Other tanh running 2 F40T12's, I have no idea what this means. I am currently using T8's in the end caps.

The Coralife package is less forthcomming with info. It simply states for 2 40 watt T12. It says it is an "energy efficient" eletronic ballast that can save up to 35% energy. Not much help there. 

so I have been reading up on overdriving the bulbs. what can I do, at least with the ballast that provides information. The help is greatly appreciated. I have had my 55 gal in operation for 14 years. I am looking foward to an overhaul.


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## GulfCoastAquarian (Jul 30, 2002)

Well since these ballasts do not seem to be load-sensing, they may behave differently, but at the very least, you'll be able to use both outputs from either ballast to overdrive a 40 watt bulb 2x and probably end up with about 1.5x the output. 

So you could take those two ballasts and run a pair of 40 watt bulbs at 2xODNO for a total of around 120watts.
Or
Just run the ballasts directly into four bulbs for 160 watts, but take up twice as much space.


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## hubbahubbahehe (Sep 13, 2003)

at home depot, they have a 4 foot fixture with a instant start electronic ballast for T8 bulbs. Like Wasserpest said, it's easier to find daylight bulbs for T12's.... so can i buy those philips T12 daylight bulbs 6500K and place them into this fixture that was made for T8 bulbs??


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## Wasserpest (Jun 12, 2003)

You should be able to use T12's instead of T8's. Since the T8's only need 32W, it is possible that the 40W T12's are underlit.

On the other hand, you could check your local electricians/lighting supply stores to get daylight T8's. You might even get them at Graingers.

Also, you can order dedicated bulbs in T8 size from Big Als and the likes, for ex ZooMed Florasun.


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