Lifespan of T5s?

[d3rryc]

What's the expected lifespan of a T5 bulb? My light rig has six bulbs, two of which are actinic. The actinics run 7AM - 9PM, and the other four run 8AM - 8PM. They are not being overdriven to my knowledge (although I need to confirm that). The reason I ask is that I've got a few corals that are bleaching a little, and I can't find a chemical reason to explain it. I read something recently on RC saying it might be possible that my bulbs were getting too old and creating problems for the zoozanthellae, which would result in bleaching. Any thoughts?

[Gseclipse02]

how old are the bulbs in the unit ??

[jc]

I read from one post that overdriven bulbs should be changed every 6 months. So if you don't overdrive then you get at least 6 months.

[alton]

Safe bet is 12 months. Now is a good time to buy a light meter so you know exactly when to change. Because it could be 8 months or they could last longer than 1 year. I run my MH around 18 months checking monthly with a light meter

[d3rryc]

Bulbs are probably almost 18 months old. I'm starting to doubt the manufacturers' claim that T5 bulbs only degrade about 10%... ; ) Would the drop in output account for the bleaching I'm seeing from a couple of corals?

[Gseclipse02]

i would think so put any sps under poor lighting and it turns white .... well this happened to me when frags fall under rocks same theory i think

[Gseclipse02]

I read from one post that overdriven bulbs should be changed every 6 months. So if you don't overdrive then you get at least 6 months.


i heard it was 6 months for PC lights

[cpreefguy]

Overdriven T5s will need to be replaced about 3x as often as T5s not being overdriven.
So about 6 months for overdriven, and 18 months for non-overdriven.

[alton]

8 months to a year for CFL's.

[labrown]

What do you mean by being overdriven?

[cpreefguy]

What do you mean by being overdriven?

That is when you put them on a bigger ballast, driving them over their listed wattage.
You can overdrive them at different rates, but it is not really a cost efficient way to get more light output. You will be replacing your bulbs so often that the cost will catch up with you, fast.
Depending on how much you overdrive them, it can decrease their life to as little as 3 months.

[d3rryc]

You can hook up a T5 bulb to a ballast that is more powerful than the one the T5 was designed for. You get greater output from the bulb, but at the expense of shortening its life.

[alton]

For a little clarification in the 46" T5 line there is T5 28 watts, T5HO 54 watts, and T5VHO 80 watts.