T5 HO vs LED

[Dan]

Hi guys,
I'm sure this has been brought up a fair few times but how on earth do you go about comparing T5 to LED.
Basically i currently run 126 watts of T5HO on my tank, I'm quite interested in switching to LED when my bulbs need changing, there is a guy local to me who does custom LED and seems really well priced compared to most the expensive brand units.

His advert:
"Well its here. Blue Cree imminent !!!!!!
New Cree xp-e Supernova Whites output. 110-120 lumen @ 1.5w 150 degree light angle 23621-25768 mcd. candella (intensity).
Whites . Blue coming very soon !!!
Brightx4 72 lumen @0.72w 120 degree light angle 22282 mcd. candella (intensity)
Blue, Red available. Can be used with manual and remote controlled dimmers.
Whites are 6,500 kelvin
Red are 620-630 nm
Blue 463-475 nm (Dom. Wavelength nanometer) "

Basically its all gibberish to me.
First off i'd like to know if these are any good for plant growth, and secondly is there some sort of conversion numbers as to how many of those LED's i would need to have to same sort of lighting as i do with my current T5's?

Any help appreciated.
Dan

 

[ian_m]

Quick look at Arcadia T5 tubes, for instance, their T5HO tubes give 90lumens/Watt, so for your 126Watts is 90 x 126 = 11,340lumens.

Thus using the less efficient LED's (Cree's best is about 70lm/Watt) 11340/120 = 94 LED's job done...

Issues now are, affording 94 LEDs, powering 94 LEDs, heatsinking 94 LEDs and mounting 94 LEDs "nicely"

 

[Dan]

Appreciate the post Ian, exactly what i wanted. He's charging £3.50 per module which i assume is one light? and that's going to be taking me way into the territory of already established LED brand's price brackets. Ah well at least i've learned something new haha.

 

[ColinCook]

From what I have read there are a few other things to take into acocunt rather than just pure wattage/lumen output.

Flourescents emit a 360 degree whereas LEDs are directed. Even using a reflector with flourescents will lose some output but is better than without.

LEDs seem to emit in a more usable wavelength whereas as flourescents emit a wider range of the light spectrum including a lot of light where it does nothing for plant growth.

I'm certainly no expert and only repeating what I have read (as I'm currently looking into LEDs too) but they are certainly becoming accepted for marine coral growth, hydroponics etc so must be getting to the quality where they are becoming a usable alternative.

I totally agree about mounting/heatsinking etc. Powerful LEDs need decent cooling and mounting to something which will dissipate the heat. The LEDs themselves will remain cool to the touch but the circuitry itself gets very hot.

Also - for plant growth the power savings are arguable. If you have 94 LEDs at 1.5w each then you will be using more power than your T5s!

Looking at the commercially available options certainly doesnt show much, if any of a power saving and although there is no ongoing tube cost the actual purchase costs are high.

I'm looking at standard LEDs for my unplanted tanks but will certainly consider a CREE-based hood for my 260l planted tank and am waiting on costs at the moment. It would need to be economically viable though.

Looking at the description you have written it seems like the same chap I've been speaking too - if so then he is a really nice bloke and has some photos of planted tanks too.

I currently run a D-D Razr 2x54w with reflectors on my 260l 4ft tank but feel it is overpowered and I do suffer some algae problems. The tank is low tech and uses TMC Nutrasoil and I dose with Flourish and Flourish Excel

 

[ian_m]

Gives you a rough idea on brightness.

However

• LED's tend to be more focused thus all the light is pointing down, unlike T5 tubes (unless you have reflectors), thus you can probably use considerably less than 94 LED's.
• Using higher power single LED's (eg 3W or 5W or even 10W) means less wiring and even greater efficiency and hopefully lower cost for same lumen output.
• You can mix and match, white, blue & red & green and vary to alter you colour rendition to suit what you think looks nice. Adding a few blue LED's to all white seems quite common.
• Plants don't generally care about the "colour" of the light, other than having enough to grow. LED or T5 lights plants don't really care.
• Heat is the killer of LED's, which is why people have aluminium heatsinks, fans etc on the back of their LED lights.

 

[ian_m]

LEDs seem to emit in a more usable wavelength whereas as fluorescents emit a wider range of the light spectrum including a lot of light where it does nothing for plant growth.

Not going to get into too much of an argument about this, but wrong, plants don't really care T5 & LED's both OK for plants.

 

[ColinCook]

Cheers Ian - as I said, just relaying what I've read.

Spectral growth seems to be quite a commonly accepted argument though otherwise why would we use anything except standard white tubes for plant growth instead of 'hi-gro', 'gro-lux' etc?

I've read that different spectra is needed for different types of growth and it seems pretty universally accepted that the blue and red ranges are of far more benefit to plant growth than the green. I think it is called the photosynthetic action spectrum?

I think my point is that LEDs can be chosen to be brightest in the most usable spectrum of light whereas many fluorescents may be more powerful in total lumens but may not neessarily be providing the highest lumens at the right part of the spectrum. I'm guessing though that those bulbs designed especially for plant growth will be optimised in those frequencies?

I didnt say that T5s or LEDs are better or that plants care which - I pointed out merely the spectral issues which may be raised and that total lumen is not the only issue

 

[ian_m]

Spectrum...doesn't matter...does it? | Page 3 | UK Aquatic Plant Society

 

[ColinCook]

Yep - definitely a point of discussion. There are just over 400,000 results discussing it on Google and on several of the other aquatic plant forums. It can be argued till the cows come home but I prefer to go with the proven scientific knowledge of photosynthesis rather than the constant inability of hobbyists to agree on anything. Even your link doesnt seem to have any general consensus and seems to go off topic to discuss every other aspect of plant growth. I should also point out that quoting pure kelvin is not a spectrum but a temperature curve. Spectrum is a range of light throughout the (visible) light range. My point was that (in my opinion) plants do respond better to certain wavelengths at certain intensities than others. NASA have been doing experiments for years on using LED lights to grow plants in space for nutrition and have even scientifically proven that certain parts of the spectrum have provided different nutritional composition.

From your own link was this scientific experiment which seems to show the opposite of what you say - again all for discussion http://www.apms.org/japm/vol15/v15p29.pdf

But - its all up for opinion and discussion. I certainly wouldnt call someone else wrong on it.

 

[Iain Sutherland]

just to throw into the mix, im not so sure you can simply compare lumens to equate the number of led's needed. I run 3 grobeam tiles each with with 10 cree XP-E's on a 120cm tank, having 90+ leds would give you a crazy amount of light as 30 is more than enough for high tech planted.

As far a spectrum and photosynthesis... the simple answer is that for our needs it simply isnt worth thinking about, any spectrum from commercially available bulbs will grow plants, its all the other variables that need you concern

 

[Dan]

Seems this topic is a little bit of a can of worms! let me try and approach it from another way then. My aquarium is 4x2x2 110 or so US gallons, 400 litres. If you were buying the LED's i mentioned at the top of the page, how many would you buy to get a decent medium light (not so much that your super high tech, but enough that you could give most plants a good crack).
Cheers
Dan

 

[dw1305]

Hi all,

I should also point out that quoting pure kelvin is not a spectrum but a temperature curve. Spectrum is a range of light throughout the (visible) light range.

This is the colour map of theoretical kelvin temperatures, elemental iron (Fe) heated to 6500K corresponds approximately to our blue sky, which is why 6500K is "natural daylight".

I haven't got much to add, as without a PAR (or even better a PUR meter), it is all just conjecture.

Spectral growth seems to be quite a commonly accepted argument though otherwise why would we use anything except standard white tubes for plant growth instead of 'hi-gro', 'gro-lux' etc?

A lot of us use standard white tubes (I do, they are cheap), and so do a lot of the hydroponic "Tomato"* growers, who tend to know where most "bang for their buck" is.

Have a look at these threads: <Marketing blurb and hype regarding spectrums... Don't believe a word of it ! | Page 3 | UK Aquatic Plant Society> & <Do t8 lights really degrade over time? | Page 2 | UK Aquatic Plant Society>

Plenty more are available as it is quite a hot topic.

* other plants may be available

cheers Darrel

 

[Samjpikey]

Hi all .
I have just made my own led light .
I used 30 x 1 watt bridegelux LEDs .
After the math they come out at 1.2 watts really , I bought the LEDs (plus 10 royal blue leds ) along with pln 48 60 mean we'll driver and compound glue for £57 pound.
It's over my 100x30x40 cm tank , but it would be nice to test them on a par meter ,

Hi all .
I have just made my own led light .
I used 30 x 1 watt bridegelux LEDs .
After the math they come out at 1.2 watts really , I bought the LEDs (plus 10 royal blue leds ) along with pln 48 60 mean we'll driver and compound glue for £57 pound.
It's over my 100x30x40 cm tank , but it would be nice to test them on a par meter ,

 

[ian_m]

A high efficiency T5 tube will beat Leds on lumens per Watt. High efficient T5's start at 110lumens/ Watt going upto 150 and more. These are suited for Office/factory lighting and not fish tank use as tend to be long and require specialized ballasts.

 

[sciencefiction]

A high efficiency T5 tube will beat Leds on lumens per Watt. High efficient T5's start at 110lumens/ Watt going upto 150 and more. These are suited for Office/factory lighting and not fish tank use as tend to be long and require specialized ballasts.

If you interpret lumens as light intensity visible to the human eye, then T5s are brigther than LEDs.
I've got LEDs (cree 45x3W crees over a 5f tank) and it's some powerful stuff. It burned holes in my emersed plants I had to lift the light unit up miles away from the surface. But they give nice natural shadowy effect.

 

[Troglodyte]

Hi Dan,

If I was to add anything here it would be along with Ian_M statement

Issues now are, affording 94 LEDs, powering 94 LEDs, heatsinking 94 LEDs and mounting 94 LEDs "nicely"

check to see if they do returns and are easily contactable. What is the guarantee period for the light and starter/driver unit? Does it comply to the aquarium lighting standards?(if UK/EU). Do they have a record of their failures or returns? (Mean Time Before Failure, MTBF). What LED/driver protection are on the units.(There are a variety of types most have none.) Ask for a PAR diagram showing the output of light. Never assume anything always ask if it is priced per LED unit.I would do all this before parting with cash.

On the lighting information that was all gibberish to you I can tell you the only bits that are really of importance are the following parts for me.

1.5w 150 degree light angle

this states the LED is 1.5 LED watt type and has 150 degree light angle coming out of the LED.(most likely with optic fitted)

0.72w 120 degree light angle

this states 0.72 watt LED type and has 120 degree light angle coming out of the LED housing.(most likely with optic fitted)

Red are 620-630 nm Blue 463-475 nm (Dom. Wavelength nanometer)

This is just explaining the colour frequency as different colours have different colour frequencies. Pretty much like tuning in a radio to receive different radio shows. However in this case we are tuning in to get different colours.

There appears to be a lack of the quantities of used LEDs described for me as this would let you know if they are being overdriven or not. (This reduces the lifespan of the LED)
Other than that my first question is what are you trying to achieve? To match your currently lighting units as described initially in your post. If this is the case follow Ian_M solution. The only issue is it will not match the light spectrum being used. You will have to decide this, as it is subjective to the user.
Hope this helps?