Lifespan of T5 HO bulbs?

[sir_dudeguy]

how long does are T5 HO bulbs good for? I was thinking right around a year? I know they'd RUN longer than that...but that doesnt necessarily mean they're putting out the right light...right? This is assuming you run a 10-12 hour daylight period.

[cowboyswife]

When I purchased mine, I was told to replace them every year.

[WaterKeeper]

There seems to be some controversy over their life span. Original claims were that they lasted 2-3 years. Reports these days give about 1.5 to 2 years. As you know, it is not actual lifetime till the tube fails but the ability of the tube to produce sufficient PAR and maintain color temperature as they age. It would be nice if someone would do spectral and PAR testing on T-5's as they age. Unfortunately, there is far more on MH lights than fluorescent of any type.

Anyway, unless you have a PAR meter and check original output vs. the tubes as they age, I would only consider using them for about a year and a half.Maybe Sanjay or The Grim Reefer would have a better handle on this than I.

JMO

[blackheart]

I agree with the waterkeeper i wouldnt use it past a year and a half. It will still put light into you tank but will have very low par values, therefore it will not do anything for the corals.

[sir_dudeguy]

Thanks all :)

Also, is there a way to tell just by looking at the tank if the bulbs arent good anymore? I'll be switching to t5's sometime soon and will prolly run them for a year and 3 months or so at first. That is unless i can get a PAR meter to tell me if its still good. I'll be using either ATI or Giesmann bulbs if that makes any difference.

[WaterKeeper]

<a href=showthread.php?s=&postid=9409001#post9409001 target=_blank>Originally posted</a> by sir_dudeguy
Also, is there a way to tell just by looking at the tank if the bulbs arent good anymore?
Nope, unless you have a very good memory. ;)

The change in the output of any type lamp is very subtle and is hard to judge over long periods of time. The same goes for spectral shifts. The observer gets accustomed to the current apparent color temperature and tends to forget how the tank looked when the lights were new. Hence the use of meters that don't have our human, judgemental values.

[sir_dudeguy]

lol figured. Thanks :) I doubt this would work, but i'd be curious to see if it does...but what i'll do is take a picture of it when i get it, and then take a picture every so often (from same spot, all indoor lights turned off besides the bulb, let the bulb run the same amount of time before taking the picture, etc...) to see if by a camera you can see any difference. Like i said, i doubt it will work, But hey, i'd be interested in knowing exactly how much different the light looks after a year or so, you know?

[WaterKeeper]

That might be possible but my guess is that it would be hard using a digital camera. Instead, you could use a good old film carmera with, preferably something like Ektachrome Pro series slide film at the same F-stop setting, distance and timing. I've done that for checking tanks in the past and, with a good color reversal film, you can see differences in a tank over time. The only problem with this method is that, hopefully, the tanks inhabitants grow and prosper as time goes by, changing the precieved white balance.