T5 Life Cycle?

[davy jones]

Hello, im confused as to what actually burns out the t5 bulbs. Is it the on off cycles that the bulb has to make over the 9-12 months OR is it the total hours used?

 

My question is, if you run the bulbs for 4 hours a day will that extend the life of the bulb? Or is it the fact of turning on and off that kills the life?

 

My thoughts are this: As i have a LED/T5 hybrid light, i will run the LED's to a higher percentage and have the T5 bulbs on only for 4 hours if it will extend usable bulb life. But if it is the on of cycles that kills the bulb then i will instead run the t5 for 6-8 hours a day and the LED at a lower percentage (also extending the life of the LED's per my understanding)

 

For those of you who know much much more than me on the subject your help is appreciated!

[evilc66]

It's a combination of both. The biggest detractor to the life of the bulb is the igniting of it. The high energy used to create the spark that ignites the mix of gasses in the tube slowly erodes the electrodes at each end of the bulb. The type of ballast used (program start, pulse start, etc...) will affect this also. The phosphor does also break down over time due to heat while the bulb is lit, but it has far less effect on the life of the bulb. One other factor that can shorten the life of the bulb is overdriving. This isn't very common any more, as you need specialized ballasts to do it, but it increases the heat at the electrode, which will also significantly reduce the life of the bulb, especially if the bulb ends are not cooled.

 

In an environment like a reef tank, you won't be able to do anything to significantly extend the life of the bulb. You will have to turn them on and off every day no matter what, which will be the greatest thing that will shorten the life of the bulb, so running it for 4 hours or 8 hours a day won't make any difference in the life of the bulb.

[davy jones]

Good to know! Im running an ATI sunpower that Dave retro-ed 6 led pucks in. But if the hours on the bulbs wont effect it much i think im gonna ramp the led's down some and have the t5's on about 6 hours a day instead of 4. If they are only gonna last for 9-12 months anyways might as well get the use outta them!