PDA

View Full Version : How to test T5 bulbs?

FISHRIPROCK
07/28/2016, 06:25 AM
Anyone know a way to test T5 bulbs? Specifically if they are still effective.
hann1bal
07/28/2016, 08:16 AM
A PAR meter is the best thing I know of
Ron Reefman
07/28/2016, 09:09 AM
A PAR meter is the best thing I know of

And even a PAR meter has very marginal use with determining if a t5 bulb is still 'good".

Yes, it can tell you if there is still output in the 400nm to 700nm range. But the issue people have with t5 bulbs over time isn't the total output, it's that the spectrum of the bulb shifts more red as it ages. That's still in the PAR range and will register on a PAR meter. But do you want that bulb? Your corals want blue spectrum not red. And algae uses red. The PAR meter can't help with that question.
FISHRIPROCK
07/28/2016, 10:04 AM
So what would the schedule be for replacing. Understanding it depends on hrs per day the bulb is on, quality out of the package when new and possibly 20 other fators.

Yearly? Bi-annually?
solitude127
07/28/2016, 11:19 AM
So what would the schedule be for replacing. Understanding it depends on hrs per day the bulb is on, quality out of the package when new and possibly 20 other fators.

Yearly? Bi-annually?

I change mine every 10 - 12 months.
gus6464
07/28/2016, 11:34 AM
Programmed Start ballast - 12 months
Rapid Start ballast - 6 months
FISHRIPROCK
07/28/2016, 01:10 PM
10-4

Thanks for the info.
hkgar
07/28/2016, 01:54 PM
And even a PAR meter has very marginal use with determining if a t5 bulb is still 'good".

Yes, it can tell you if there is still output in the 400nm to 700nm range. But the issue people have with t5 bulbs over time isn't the total output, it's that the spectrum of the bulb shifts more red as it ages. That's still in the PAR range and will register on a PAR meter. But do you want that bulb? Your corals want blue spectrum not red. And algae uses red. The PAR meter can't help with that question.

Actually I understand it the best coral growth is around 6700K, but we don't like the color in our aquariums and the corals do show better color at the higher K levels. I use a 8 bulb 80 T5 above my tank and 1 of the bulbs is the Geiseman Tropic 6500k bulb