View Full Version : Do LEDs dim over time? How can you tell?

Silly clownfish
03/31/2016, 01:14 PM
I am just randomly wondering about this - no discernable problems. My Photon 32 is almost 2 years old & I was wondering about longevity (after replacing VHO bulbs again on my old tank:thumbdown)

Any thoughts or experience?

I am looking to borrow a PAR meter from my local reef club (main reason I joined) so I can at least have current readings as a baseline.


03/31/2016, 06:15 PM

They should last about 5-6 years, they are rated for 10-12 years but over a tank they may degrade faster. Most LEDs are at about 70% of their original power at the end of their rated lifespan.

Silly clownfish
04/01/2016, 07:46 AM
Thanks Logan,

So since most of us don'trun our lights at 100%, would it make sense to bump the up on an annual basis? Say you want to max out at 70%, start at 70% and then bump up 3-5% a year until you are running at 100% (which by then would be 70% of the original power)?

Is the reason they degrade faster over a tank because of humidity? That is part of why I use a full glass canopy. Just wondering if it helps the lifespan of my lights. Yes, I know ift blocks some light.


04/08/2016, 01:53 PM

I would recommend adding a little each year, you can keep track using a par meter if you have access to one. Maybe 5% or so annually, or simply lengthening the time you run the peak intensity at will work.

Also, it is mostly the moisture, and also the fact that these are high-powered LEDs that are on 12 hours a day, while most lights are on for only a few hours at a time, like household or office lights.