HELP! Low par on Gen2 Radions

[Deep Elem]

I have two xr30s I bought used. Tank is 180 so 23” deep. At 100% power with Blues at 100% white at 75% and green/red at 25% I am getting 170 PAR 8” from surface and 40s at bottom. Could diodes be bad?
I also have a glass top on tank.

wish I had rented meter sooner- I have been running at 60% to date so less than 50 par at top!

 

[mfinn]

Take the glass top off. Try testing then.
If you are worried about jumpers, get a screen top.

 

[_AV]

Do you see all LEDs turning on when the unit is on? Older radions are notorious for having half of LEDs burned out. Also, LEDs do lower intensity with age. Although, I'd say that such a drop in PAR is very significant. Agree that you should test without the glass top to be sure.

 

[Camaro Show Corals]

Glass tops are way out of style these days since they get dirty fast and lower part. Get a screen top, lots of options as well.

 

[Deep Elem]

Even with tops off highest is 200. I’m thinking I bought lights with exhausted diodes.

 

[_AV]

Very possible indeed. Especially if both light fixtures show very similar low numbers. Other possibilities include the main board inside corroded, or too many LEDs burned out completely.

 

[blasterman]

Glass tops are way out of style these days since they get dirty fast and lower part. Get a screen top, lots of options as well.

I run a glass top and don't care what's 'in style'. I'm not a teenage girl hangin' at the mall and frankly don't give a hoot what others are doing. The lemming train to UV LED's is proof enough.

My top off per week is one gal of water. I save the rest of my money I could be wasting on ATO and other junk and spend on other things. Water is not free.

Glass maybe takes out 10% of light if it's wet....a sentient mammal compensates by turning their LED unit up. Oh wait, it's a Radion...one of the highest prices fixtures in the industry that is blowing diodes because they put the cheap thermal rush inducing driver in them. Meanwhile LED fixtures I made in 2007 are still running 24/7. That's what we should be talking about. Not glass tops...which I think are great.

You do not 'exhaust' an LED diode. Either the driver is bad, or the fan is dead running the LEDs at too hot a temp.

 

[_AV]

You do not 'exhaust' an LED diode. Either the driver is bad, or the fan is dead running the LEDs at too hot a temp.

LEDs do fade over time and lose original intensity significantly as has been explained and demonstrated repeatedly:
https://www.digikey.com/en/articles/understanding-the-cause-of-fading-in-high-brightness-leds

 

[oreo54]

LEDs do fade over time and lose original intensity significantly as has been explained and demonstrated repeatedly:
https://www.digikey.com/en/articles/understanding-the-cause-of-fading-in-high-brightness-leds

Only an issue if designed poorly.

Operating the LED according to the manufacturer’s thermal guidelines will reduce the rate of crystal degradation and ensure a long and bright operating life.
High-brightness LEDs tend not to burn out rapidly. Rather, they slowly fade away. A carefully designed LED lighting system can see the light source last for up to 50,000 or even 70,000 hours before the illumination is no longer sufficient for the intended job.

They may rapidly fade if they overheat (poor heat sinks, bad fans, over driven).

original intensity significantly as has been explained and demonstrated repeatedly

Sensationalized statement.


And browning is mostly due to organics and high energy photons.
https://www.reef2reef.com/threads/need-help-from-diyers-led-diode-experts.680685/
Bunch of gross led photos.. ;)

CREE:
https://www.cree.com/led-components/media/documents/XLamp_lumen_maintenance.pdf

The silicone encapsulants are a good example of this degradation. The silicones used in the LED industry are polyorganosiloxanes (or siloxanes).2 Depending on their exact chemical composition, these siloxanes may be very sensitive to operating temperatures. At higher temperatures the transparent nature of the materials can quickly degrade causing an overall loss in light output from the LeD lamp. The energy of the photons emitted from the chip itself can also damage the siloxane material, further reducing its transparency, causing additional lumen depreciation. Thus, the higher the drive current, the more light being emitted from the chip and the faster the lumen depreciation of the lamp. Higher drive currents also result in higher operating temperatures of the LeDs, compounding the depreciation issue