Are the T5 bulbs any different than the T8s?

[Mordachai]

I've got a dual T5 light that is billed as "HE" (High Efficiency) 2x28W.

Most of the stuff I read about lighting uses W/gallon as a rough metric for low/med/high lighting.

But do the T5's punch above their weight? Is 1W of T5 == 1W of T8?

And how does one work in the difference between a standard CFL vs. a Full spectrum 6700K CFL, in terms of W/Gallon?

 

[musicmarn1]

great question hope you get a bunch of answers !@! im learning about lights, i thought the only difference with T5 was that they were smaller so you can get more of them in the space.....be nice if they had more *punch* but i couldnt find any evidence of that in my research, i wasnt looking at watts since thats not what the plants use just the efficiency of getting the same spectrum light to the plants

standard cfl wont work if its not in the 65k region i thought, again im very new to this but i have been trying to do the resarch, it has to be daylight full spectrum cool light 65k or higher, again watts dont matter what does is color temperature and the spectrum of the light, there was a good you tube video on CFL usage ill try and find it

 

[Chris J]

I'm not 100% but I do believe that T5's have more PAR/PUR (the important measurement along with spectrum of light) per watt than that of T8's of the same wattage... But again I'm not positive on that. Also if you are trying to account for improper spectrum, you should just change the bulb because you will wind up growing algae rather than your plants. I have a reef tank but have never kept a planted freshwater so I'm just trying to use my reef knowledge (I'm a newbie to reef so I was doing a lot of similar research on lighting as well). PAR/PUR (important) is a measurement of light put off (not necessarily visible but also ultraviolet and infrared), Lumens is Visible brightness (not important for photosynethic organisms) wattage is just how much power is used by the light (not necessarily higher power = better, it's equally about the type of light and which color temp. of light as it is power) if you know all of this already I'm sorry for rambling about it.

 

[BBradbury]

Hello Mord...

The T5 will provide more intense light, but will shine it over a smaller area. The T8 will provide more watts, and shine over a wider area. The light produced by the T8 won't be as intense, though.

You'll need a fixture that will hold multiple lamps, if you elect to use T5s. This way you guarantee even light coverage over the entire bottom of your tank.

B

 

[aquandrew]

the T on for lightbulbs is what measures the diameter so T5 would be smaller than T8. A 28w T5 produces the about the same amount of lumens as a 32w t8. T5HO 54w has 5000 lumens where a T8 32w has only 2900. T5HO go up to 80watts for one bulb and T8 only goes up to 51 watts. T8 and t5ho produce just about the same lumens per watt as each other so the only reason T5HO is considered stronger is because you can have more watts per gallon with the strongest bulbs. full spectrum is just something manufacturers put on the box. 6500k is said to be "full spectrum" because it has more even amount of the color spectrum whereas a 10000k light would be more of blue spectrum and 5500k would be more of a yellow spectrum. 6500k is considered best for growing plants

 

[Chris J]

I also don't know how High Efficiency factors in.

 

[Mordachai]

I also don't know how High Efficiency factors in.

This is what leads me to believe that the T5 are higher lumens/watt...

the T on for lightbulbs is what measures the diameter so T5 would be smaller than T8. A 28w T5 produces the about the same amount of lumens as a 32w t8. T5HO 54w has 5000 lumens where a T8 32w has only 2900. T5HO go up to 80watts for one bulb and T8 only goes up to 51 watts. T8 and t5ho produce just about the same lumens per watt as each other so the only reason T5HO is considered stronger is because you can have more watts per gallon with the strongest bulbs. full spectrum is just something manufacturers put on the box. 6500k is said to be "full spectrum" because it has more even amount of the color spectrum whereas a 10000k light would be more of blue spectrum and 5500k would be more of a yellow spectrum. 6500k is considered best for growing plants

Thanks for the response...

The diameter is measured in 1/8" increments, hence T5 = 5/8" diameter, and T8 = 1" diameter.

It's the lumens / watt that has me confused

Clarification: T5HO & T8HO are about equivalent in lumens/W, or T5(HO) & T8(std) are about equivalent in lumens/W?

 

[aquandrew]

they are nearly equivalent in lumens per watt but T5HO bulbs go up to 80 watts and T8 goes to 51 watts so you can achieve more watts per gallon with T5HO

 

[Mordachai]

Thanks

I also found this reading on this forum:
Lighting an Aquarium with PAR instead of Watts

Seems to have some comparisons of different lighting techniques, and some info on lux vs. PAR and other technical details of lighting.

 

[wildroseofky]

Here is a handy little chart I was given on here to help me with my lights. Kinda simplifies everything.

 

[aqua_chem]

The T5s you have are being billed as 'high efficiency' as a marketing ploy, not necessarily in a technical way.They are higher efficiency than T8, but not really more light. T5HO have them both smoked quite handily.

I wouldn't bother yourself too much with lumens/watt. Our princess is in another castle.


The link that Mordachai put up is the current gold standard of FW aquarium lighting. The chart that Wildrose has came from a previous incarnation of that same page, but Hoppy has, for whatever reason, decided to abandon it. The catch to that is that is assumes near-perfect reflectors that increase light around 3x from no reflector. Most lower end reflectors only do 1.5-2x increase, such that that chart will overestimate the light levels.

The watt/gall, lumen/watt, lumen/gallon, or what-have-you rules were designed in the age when T8 was more or less status quo, and it wasn't a good rule then. As you see, things have gotten much more complicated in recent year.