# F40T12 Vs F32T8



## Philip C (Jan 1, 2007)

I was looking at bulbs and found the T8 put out more lumens per watt than the T12.
For example the F40T12 was rated at 2450 lumens and the F32T8 is rated at 2800 lumens. So my instint was to go with the T8 because more lumens for less watts. So when ask how many watts per gallon, well I’m now at 64 watts instead of the 80, this drops my watts per gallon to 1.16 from 1.45. On the other hand my lumens went up to 101 per gallon from 89. So is watts per gallon really the best form of measurement?

Another thing I noticed, the Plant and Aquarium bulbs were from 10 to 15 dollars where I found a package of 2 of the Philips Daylight Deluxe for only 6 bucks. This is a 1/5 of the price at the same k values at 6500k. Is there any advantage of going with a bulb labeled for plants when the daylight deluxe has the same k value? 

Thanks
Philip


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## John N. (Dec 11, 2005)

You're correct the watts per gallon rule doesn't work out as properly as one would hope. The T8 bulbs you chose are better than the T8 bulbs and are the ones I would have chosen.

The speciality bulbs are not much different then the cheap bulbs. With all aquarium products, they always get marked up in price because that are marketed for aquariums. As long as they have a similar output and color temperature spectrum then you won't notice any difference between the two. 

-John N.


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## ruki (Jul 4, 2006)

Philip C said:


> So when ask how many watts per gallon, well I'm now at 64 watts instead of the 80, this drops my watts per gallon to 1.16 from 1.45. On the other hand my lumens went up to 101 per gallon from 89. So is watts per gallon really the best form of measurement?


You have just clearly demonstrated that the watts/gallon is a rough estimate and not a rule. It's good for people who aren't interested in doing calculations more complicated than one simple division or multiplication. 



> Is there any advantage of going with a bulb labeled for plants when the daylight deluxe has the same k value?


Usually not. But the Kelvins value for a tube is also something of an approximation when used for flourescent tubes. A blackbody radiation curve is a pretty smooth curve and a fluorescent light curve is quite spikey. Tubes with different spikey curves can be marketed with the same Kelvins number.


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## Muirner (Jan 9, 2007)

I will have the same bulbs in my new hood once i build it, it sounds like your getting your lights from Home Depot... at least that's the same deal i'm getting on bulbs from there.

My question is, the only bulb protector sleeves i can find at home depot are T12's but they are in the proper length, but i plan on using T8's (like the one's mentioned above) but will the sleve be to much? The lights should be about 8" off the water, with an open air back. (sorry to semi hijack)


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## Philip C (Jan 1, 2007)

You are right, I got them at Home Depot 
My LFS wants 20-40 bucks per bulb while I've been using $2 cool whites for the last 10 years and everything seems to be doing well. Just figured try something different. The neat thing, for now I have both fixtures above my tank, the old T12 and my new T8 with my new Daylight Deluxe bulbs, my plants have been bubbling ever since. 

Because the fluorescent light cure is so spiky, would it be best to use two different types of bulbs in combination?

Philip


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## Burks (May 25, 2006)

Philip C said:


> Because the fluorescent light cure is so spiky, would it be best to use two different types of bulbs in combination?
> 
> Philip


Are you talking about something like a T8 and T12 in the same fixture or two different colored bulbs?

For the first part I cannot answer. Shouldn't be a problem.

The second I can. The reason I like multi-bulb fixtures is the ability to use different color combinations. I really like my 8500k and 6500k T8 combo, the 10,000k and 8500k looks really nice as well. So if you have a bulb that peaks in one area of the lighting spectrum you can use another that peaks someplace else to cover the range (make sure it's in the acceptable range for plants of course).

BTW: In my two shop lights fixtures: The first one has two 4100k T-12s and the second one 8500k T8 and one 6500k T8. Nice blend of colors and the plants are doing ok considering there's no CO2 or ferts.


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## Philip C (Jan 1, 2007)

Burks said:


> Are you talking about something like a T8 and T12 in the same fixture or two different colored bulbs?


I've read that the T12 and T8 use two different types of ballast, so I'm not sure if they are backwards compatible. 
I was asking about two different color bulbs, so if you had two to pick from, what two would you pick?


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## Muirner (Jan 9, 2007)

The fixture i purchased is T8/T12 compatable, i'd be able to run the two different bulbs. Or put the 10,000k's somewhere, and the 6500k's elsewhere. I just am unsure of where to get the 10's at... I'll check home depot again tomorow.

Soon enough i'll unvail my hood that i've been making for the past week or so... Should have enough light for my 55gal.


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## Burks (May 25, 2006)

I am running both T-12 and T-8's on the same ballast. I just wasn't sure if you could mix the size of bulbs on the same fixture.

You aren't going to find 10,000k bulbs at Home Depot, sorry. Zoo-Med makes the, they are called "Ocean Sun". 

Personally I would just get two 6500k bulbs. I ordered a package deal of bulbs off Ebay and the 8500k bulbs were in the package, kind of hard to find. It gives off a pink light so it isn't for everyone.


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## Muirner (Jan 9, 2007)

Eh not a fan of pink light. I may get A T12 bulb for the upped wattage to run along with my T8. I just need the proper color temp. 

Are you running protector sleves on yours?


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## Burks (May 25, 2006)

Muirner said:


> Are you running protector sleves on yours?


Nope.

Although I don't think it'd be a bad idea. Depends on how much light I'd lose though.


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## Muirner (Jan 9, 2007)

That's what i'm worrying about. If i use a protector sleeve will i run into an issue with it causing light loss. Hopefully this hood is done soon and i can show you my work


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## Burks (May 25, 2006)

Another thing I don't like about the sleeve is the possibility of water buildup inside of it. I have my lights about 6" above the water line and have yet to have any water buildup. But when the lights are enclosed.....I'm not so sure.


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## Muirner (Jan 9, 2007)

In the hood i have under construction, it will have the lights about 6-7" off the water, with an open back, thus plenty of air exchange.  The only thing i worry about is light loss now because of that....IDK what to do, but it maybe some modifying again.


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## Burks (May 25, 2006)

The light loss could be minimal as well. A couple of watts won't make a huge difference over a larger tank. 5w over a 10g is a big difference than 5w over a 55g.

Worst you can do is try it and not like it.


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## Muirner (Jan 9, 2007)

Thats what my dad and I came up with. I took pictures of the process, the boxing of it, the plywood added, primed, and soon to have the lights in, and it's already painted. I'm pretty excited.


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## Muirner (Jan 9, 2007)

What bulbs did you end up using in your fixtures? The 6500k's alone? or?? Sense there is that coupon at petsmart i was thinking of getting a 10,000K bulb, or something of the sorts, this could help penitrate to the 21" depth i'm looking for. I'm planing on running mostly the 6500k's but i have room for 4 bulbs. Suggestions? (T8 or T12's only)


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