Attention t5 users.

aslam

aslam

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Hello guys,I would like to clarify whether burning t5's without cooling them will shorten their lifespan.Your experiences and opinions would be appreciated.Thank's.
 
Read this, not sure what it means though :p

Effect of temperature
The light output and performance of fluorescent lamps is critically affected by the temperature of the bulb wall and its effect on the partial pressure of mercury vapor within the lamp.[6] Each lamp contains a small amount of mercury, which must vaporize to support the lamp current and generate light. At low temperatures the mercury is in the form of dispersed liquid droplets. As the lamp warms, more of the mercury is in vapor form. At higher temperatures, self-absorption in the vapor reduces the yield of UV and visible light. Since mercury condenses at the coolest spot in the lamp, careful design is required to maintain that spot at the optimum temperature, around 40 °C.
By using an amalgam with some other metal, the vapor pressure is reduced and the optimum temperature range extended upward; however, the bulb wall "cold spot" temperature must still be controlled to prevent migration of the mercury out of the amalgam and condensing on the cold spot. Fluorescent lamps intended for higher output will have structural features such as a deformed tube or internal heat-sinks to control cold spot temperature and mercury distribution. Heavily-loaded small lamps, such as compact fluorescent lamps, also include heat-sink areas in the tube to maintain mercury vapor pressure at the optimum value.[7]
Click to expand...

http://en.wikipedia.org/wiki/Fluorescent_lamp#Effect_of_temperature
 
Thank's alot Viper,that confirms.Just a quick question,the t5's we use in South Africa,are these normal tubes or vho.Examples of these tubes being Ati,or Reeftek.Also,does it really matter what ballast is used regarding vho tubes.
 
No worries Chris,and thanks again.Thanks Jaques for confirming.
 
Sorry for going off topic, but, how many of you guys noticed, that as the T5's get hot (i mean after a few hours) they are not as bright as compared to what they were when they were switched on? By the way, im talking about bulbs not being cooled by fans etc...
 
Hello Mekaeel,I also noticed this,it looks almost faded.Which bulbs in particular have you experienced this with.
 
aslam said:
Hello Mekaeel,I also noticed this,it looks almost faded.Which bulbs in particular have you experienced this with.
Click to expand...
Not too sure of the brand now... I got it from Marco. Apparently it is made in a very reputable factory. But I had the same issue with Geisiman aswell as Aquamedic. Im planning on installing some fans soon.
 
Cool Chris.Mekaeel,I have noticed this with Reeftek,Osram and Sylvania.Fans keep the water cool but the bulbs look the same after hours of use.
 
I used a 12 inch fan,resting on a brace blowing directly on the reflectors.Keeps the reflectors and the bulbs cool.The t5's are diy,basically 6 54watt tubes under 4 reflectors resting on the tank braces.Tank has no hood.
 
Giesemann have studied this in some detail, please find a link to the test chart here:
http://www.theaquariumsolution.com/optimum-temperature-t5-tubes

It would seem the optimum ambient temperature is around 35c, to me at least this relates to the temperature inside the light unit rather than the temperature of the lamp itself. I dont think active cooling is essential as long as the light unit has been designed to run within these temps.

Active cooling is good but i would always worry about warm moist air from the aquarium effecting the ballasts if built into the unit if air is being fanned into an enclosed unit.

Hope this helps Tony
 
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mmm....very interesting.im going to be using T5's 6 x 54w.the thing is that they will be housed in 3 reflectors.2 x globes per reflector and the globes will be qiute close to eachother:whistling: do you think that will be a problem? its a DIY unit wich is being build out of chromodeck the same stuff wich they make other light units out of.there will be fans in but only over the top to keep the balsasts cool.
 
Thanks Tony,Mekaeel,I doubt your light unit runs at or lower than 35 degrees in our hot summers especially when running all bulbs for nine hours plus.
 
Hello Clinton,where are you sourcing the chromadek from.You can check out the Ati powermodules and check where the fans are placed.I know a guy was building a t5 light unit on zeovit based on the powermodules.
 
@aslam what is the ambient temperature above your tank? More than 35c?


@clinton stanford you must keep T5 tube at least 46mm c2c apart. pref with a reflector between. Closer together and you burn the tubes due to overheating. The reflector not only improves the efficiency of the tube but also its longevity.


A little tech info here.
http://www.sfiligoi.it/files/media/CATALOGHI%20INGLESE/STEALTH%20ING.pdf

Giesemann used to have simmilar tech info at one time.

@TonyDD not sure if i am correct but running temps of the old D+D globes was 82c with a life span of 15 months (4000 hours) if i rem correct. You guys and giesemann have changed you sites and i dont seem to find this info anymore.
 
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