Lighting - Accuracy of a saleman's statement

[peter.norman]

I asked an online store for information on a lighting fixture they sell that fits my tank (Juwel Trigon 190) and this is what he responded with:

The wattage thing is a bit more confusing-sorry. The way it works is that the wattage is the amount of power you put in. Critically this is not the same as the amount of light you get out-it depends upon the efficiency of the lamp. The trick is that T5 lamps use the power more efficiently and give out 2 to 3 times more light per watt than a standard T8 lamp would. So in a nutshell a 24w T5 is "worth" 2 or 3 times more in terms of light than a 24w T8.

Does the piece about T5 being worth 2-3 times T8 ring through?

 

[Mgamer20o0]

i know t5 bulbs are better then t8 bulbs. here something i found on the net.

T12 is about 58.9 Lumens/Watt
T8 is about 93.0 Lumens/Watt
CF is about 79.4 Lumens/Watt
T5 is about 105 Lumens/Watt
T5 HO is about 93 Lumens/Watt

 

[John N.]

T5HO (high output) can easily be 2-3x better than T8 bulbs.

Given individual reflectors regular T5 can be much better than T8 since more light is directed into the tank, verse bulb restrike.

-John N.

 

[plantbrain]

i know t5 bulbs are better then t8 bulbs. here something i found on the net.

T12 is about 58.9 Lumens/Watt
T8 is about 93.0 Lumens/Watt
CF is about 79.4 Lumens/Watt
T5 is about 105 Lumens/Watt
T5 HO is about 93 Lumens/Watt

Lux is slanted to green part of lighting spectrum, 555nm(our eye's optimal viewing range), plants are most effective at using the light in the red and a little bit of the blue spectrum, this is commonly referred to as PAR, photosynthetic active radiation(400-700nm).
It's given as micro moles of light per unit area(meters^2)/sec.

Only a PAR meter will register the truly bioavailable light, not lux.
Distance from the bulb under actual conditions also is a better choice.
CF and T5's should be similar, as they are the same type of bulb, just bent(CF's).

Regards,
Tom Barr

 

[TipStylez]

Whats the T means anyways?

Really confusing to me.

 

[loaches r cool]

T is the size (diameter) of the bulb in eigths of an inch. A T8 bulb is eight-eigths (1"), a T12 bulb is twelve-eigths (1.5").

L to R T12, T10, T8, T6 (all these are interchangeable in most fixtures).

CF's are not always bent T5's, infact many are bent T6's.

I would not say they are 3X better. Maybe 30-50% better sounds better to me, all things being equal. If things are not equal, like a T12 shoplight with no reflector and crappy bulbs compared to a Tek Light with optimal polished reflectors on each bulb, then sure, maybe 3X better.

 

[ErrorS]

3 times more light per watt is really, really pushing it. This definitely isn't true for HO bulbs (as mgamer shows, they're less efficient).

Power per watt isn't everything. There is also the size factor. We can only fit so much lighting under a hood without running out of room. I think this is mainly why people like T5s so much.. you can either fit more bulbs or have enough room for individual reflectors.

With NO T12s and T8s it's basically that the T8 uses less power and outputs the same amount of light.. it's more efficient, but a 40W T12 isn't going to put out less light than a 32W T8, they'll usually put out about the same amount..
I'm sure it's the same with T5s. A 48'' T5 outputs about 2400-2800Lumens (depending on spectrums being reproduced), the same as a T12 or T8..