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Lighting Recommendation

Bhu said:
Ahhh but don't forget you should really change those tubes every 6 months as the light emissions drop drastically In some of the important output ranges... I also use fluorescent tubes for growing land plants such as basil and corriander in an aero garden and the lights need to be changed every 6 months or growth does get less and the plants start to have issues. They work perfectly mind. I get great lush growth.
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Sorry, don't agree with this... you will see plenty of folks running T5HO fixtures without changing the tubes for long periods of time. If you feel it doesn't emit enough light just get them closer to the tank. Plants get adapted to the light conditions and you don't need a sun over you to grow aquatic plants. In a 60 cm lonk tank 2x24w T5HO will grow whatever you want, even if the light drops drastically (if you are a newbie on planted tanks I would begin placing the light fixture 25 cm above the tank. If you don't use Co2 you have toooo much light). For one year this fixture has been 40 cm above my 60 cm tank and now that I'm playing harder and inject loads of Co2 I got it 15 cm above the tank... this light fixture came with two horizontal extension legs to be placed just a few centimeters above the water, but I have not been able to place the light so low without issues and the tubes are more than 1 year old right now. I would say that even if the tubes' output drops dramatically (which is true) there will be no effect for you... so save your money for something else and keep on using your old tubes. In that tank you have 58 liters but if you add gravel, plants and equipment you will find yourself with 50 liters maximum... just a rule of thumb that means nothing, but note that this makes 1 watt per liter of T5HO which is a lot of light.

Jordi
 
Bhu said:
Ahhh but don't forget you should really change those tubes every 6 months as the light emissions drop drastically In some of the important output ranges... I also use fluorescent tubes for growing land plants such as basil and corriander in an aero garden and the lights need to be changed every 6 months or growth does get less and the plants start to have issues. They work perfectly mind. I get great lush growth.
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It's been proven that tubes don't need changing like manufacturers state, it's makes very little difference to aquariums other than how it looks to our eyes.
Clive has proven this theory I'll try to find the link
 
Bhu said:
Ahhh but don't forget you should really change those tubes every 6 months as the light emissions drop drastically In some of the important output ranges...
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The Matrix at work. Manufacturers have convinced you to buy their tubes every 6 months, lovely for them, but completely unnecessary as light output hardly drops over that time.

Here is a graph of T5 HO light output. So at 20,000 hours only down to 90% of initial lumen value. 20,000 hours is 2 1/4 years. Also driven by electronic ballast to get this output.
TubeLife_zpse7de1419.png

On caveat I would give, I had some cheap T8 tubes at one time and they were certainly dimmer after about a year and half. Arcadia equivalent were hardly changed in brightness after 2 years.

Also with electronic ballasts the tube will degrade less.

Also heat is an issue. Tubes open to air last longer, tubes in a luminaire with out cooling fan (as in Ebay cheapies) last a lot less.
 
Thanks everyone for your advice.

I have order the 2 x 24watt T5 60cm from aquarium garden. Hopefully this tank will be a success 🙂
 
Your graph clearly shows a 20% drop in performance... But by then you will have a lot more demand as well due to extra plant growth. I'm happy to change mine and have noticed less growth on older tubes. Same for my MH and sodium lamps as well. But yes sure it still works. Just depends what you want which for me is maximum yield.
 
Bhu said:
Your graph clearly shows a 20% drop in performance
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Where is 20% ? Lumen maintenance is the line you are looking for, slightly less than 90% @ 20,000hours.

Actually in fact the loss of light is related to number of times turned on and off (why offices leave lights on 24/7 ?). The tube heater filaments evaporating at start up over time lead to light loss. However, if you are using something like Juwel lighting (or super modern high frequency ballast), they don't use the heater, thus tubes will last even longer. Basically, as has been researched numerous time with aquatic tubes, you will loose about 5% lumens pretty quickly, 1-2 months (you can actually buy pre burnt in tubes for lighting if you need very accurate lighting levels in industry), then virtually nothing in light loss for next couple of years.
 
I don't know maybe we read charts differently as to me after 238 days the green lumen line is nearly at 80 its clearly below 85.

Also how many tubes were used in this experiment? One lucky one, 10 or 100? Also its not the brightness I initially referred to but the wave length the tube gives off. It still may be bright to the human eye but if most of that range is in the green or yellow not much use to green aquatic plants. Anyhow, I'm happy to replace mine every 6 months as I have done for many years and had successful growths (non aquatic use) for my aquatic use I went with LED which last a good 5 years before any change in output.
 
Bhu said:
I don't know maybe we read charts differently as to me after 238 days the green lumen line is nearly at 80 its clearly below 85
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????? Where are you reading 238 days from ?

15,000 hours at 12hours per day is 1250 days 3.5 years to 90% lumen loss. Hopefully you are running a tank at 6-8hours a day which gives 5-7 years life (actually less than this as each turn on reduce life a little).

On the data sheet I have it also gives spectral shift over lifetime, which is basically none, just general lumen reduction across all spectral range.
 
An interesting read. It is clear that the technology has come a long way since the 1930's. It doesn't show comparisons to LED only previous similar technology T8, T12 etc also the fail rate has a 50% error so some may last the full 200 days given as max orthers may not. But you might get lucky and have one last 2 years. The new research will improve the lumen output per watt but still they need to test the effects it might have on health and durability etc. They also state that a lot of the research funding has gone away from this field to newer ideas such as MH and LED which might imply that the future is there and that the fluorescent tube is nearly at its peak...

ian_m said:
????? Where are you reading 238 days from ?

15,000 hours at 12hours per day is 1250 days 3.5 years to 90% lumen loss. Hopefully you are running a tank at 6-8hours a day which gives 5-7 years life (actually less than this as each turn on reduce life a little).

On the data sheet I have it also gives spectral shift over lifetime, which is basically none, just general lumen reduction across all spectral range.
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Did you say that they need to be left on for maximum life due to burn out in starting? So that's 24 hours in a day not 12. But what's your point here? Are you a T5 salesman? Ha ha ha or have you invested in fluorescent lighting technology shares? 😉 just kidding. I use cfl for my herbs. Works great but I defianately need to change them.

Can we see the data sheet? Who is it by?
 
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Bhu said:
But what's your point here?
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Just that you have fallen for the Matrix and are wasting money in changing the tubes for no reason other than manufacturers have told you to. If your "old, used" tubes are T5 742mm 35W please post them to me....🙂
 
After researching on this forum its use em til they blow then 😉 sounds like a good deal!
 
I was always under the impressions that bulbs had to be changed regularly too!
Music to my wallet by sounds of it now 🙂
 
Hi all,
I think even with LEDS you will get changes in spectra as they age, hopefully someone who knows more about them will be able to pass comment..

Modern electronically ballasted tri-phosphor fluorescent tubes basically remain as bright as they started until they fail. You don't get any cycling etc towards the end of their life span, so if the tube is lit it is OK.

cheers Darrel
 
dw1305 said:
Modern electronically ballasted tri-phosphor fluorescent tubes basically remain as bright as they started until they fail
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Modern tubes generally lose brightness over a couple of years due to the tungsten in the heater filaments evaporating, a lot when started and a bit during use, and "condensing" on the phosphor reducing its brightness. However, as you stated, modern electronic ballasts (eg like the Juwel units) don't use the heater, they "flash over" 1000Volts to start the tube, tubes will last a lot longer than conventional "olde magnetic" ballasts. The tubes finally fail when a gap appears in the tube heater, maybe as short as 20,000 hours 🙂.

dw1305 said:
think even with LEDS you will get changes in spectra as they age,
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Good quality LED's generally don't change spectra as they age, they just get dimmer. Good figures are 35,000hours to 80% lumens, which is actually a lot worse than a T5 HO tube, but you would have to not turn the T5 off to get that life time.🙄

What happens with lower quality LED's is the chip reduces in brightness with age but the packaging ie lenses/cover etc can be adversely affected by the bright light (especially the UV bit) and darken/yellow. This happens in the 1000's of hours timescale, a factor of 10-50 times faster than the LED reduction in brightness. This darkening/yellowing greatly reduces light level, blocks the blue end of the spectrum producing a yellowing/reddening of the spectrum. This issue was solved years ago by the "big boy" LED manufacturers ie Cree, Osram but is extremely common at the cheaper Hong Kong Ebay end of the market.
 
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