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View Full Version : par metre not mesuring 10 wat led chips


Coral Hoarder
04-24-2014, 04:22 AM
so i borowed a par metre off a friend and it doesnt seem to be mesuring corectly at 100% power to the fixture 5 10 wat chips 3 blue 2 white x 2 pendants the par in the tank on the botom says 20 now that inposible as i can bleach corals at 70% any one have and advice here ?

i mesured my ever grow fixture and redings were acurate so its not the metre

the only thing i can think of is the fuxture not being full spec and there for not mesuring proporly ?
i only have one kind of white led and one kind of blue led in it but it seems to grow corals well

Coral Hoarder
04-24-2014, 05:14 AM
little update par is 30-70 on avrage in the tank wich seems realy wierd i dont have any sps but my lps is growing fine even in the spots where the par is 20 o yea and boath of my clams are doing fine iv had one in the tank for a few months now 5or6 where it says the par is 9 wtf

theres no lenses in the leds could i retro fit them and make em more powerfull ?

SeaHorse_Fanatic
04-24-2014, 07:04 AM
For LEDs, from what I've read, you need to measure PUR readings (Photosynthetically Usable Radiation) not PAR.

I don't know how much PAR the blue LEDs read, but I know someone who only uses blue LEDs on his tank and grows lots of corals. I never would have believed it before. So I'm assuming he's getting sufficient PUR even if his PAR readings are low.

UV emitters, on the other hand, apparently have neither PAR nor PUR. (Any emitter in the 300-400 nm range)

LUX is another reading that doesn't actually let you know how good the emitter will be for growing corals. LUX measures visible light at the 555 nm I believe, which is not necessarily what our corals need the most (they like reds and blues, which LUX does not measure). For those of us who switched from Metal Halide to LEDs, the new lights always seem too dim, especially when dialed down, which is why most reefers make the mistake of ramping up their LEDs too quickly.

Here's a quote from the coral science website:

"For such a species, a light source containing a high amount of blue in its spectrum may provide a lot of PUR. At the same time, this light source may show a low PAR value, if all other colours are emitted in low intensity."

This is the site link:

http://www.coralscience.org/main/articles/symbiosis-4/inside-a-coral-lab

Hope that helps.

Anthony

Coral Hoarder
04-24-2014, 07:14 AM
thanks ! the thing is it mesures my other leds fine and i have seen multiple vids of it mesuring other led lit tanks heres a pic of the one im using it was built to test leds as well as halide and t5 http://i1316.photobucket.com/albums/t602/scott-tang/fish%20stuff/IMG_20140423_230908_zpsmxyec1c2.jpg (http://s1316.photobucket.com/user/scott-tang/media/fish%20stuff/IMG_20140423_230908_zpsmxyec1c2.jpg.html)

TheMikey
04-24-2014, 06:34 PM
PAR meters do not accurately measure LED intensity for a comparison to MH/T5 - it has an issue with the blue LEDs which are what make up the majority of the LED clusters.

You can actually track this revelation back to Reef Central a few years back - People would build these massive LED arrays trying to get to MH PAR readings and they would have disappointing results from LEDs because of colouration and growth issues. The issue, it turned out, was that they were almost frying corals from the intensity.

People are having better success with LEDs now, because they're putting the appropriate intensities over the tank. If you can't get the PAR readings you want, you may just have to set a low intensity and adjust until you get the results you're looking for. Your corals will let you know.

Jakegr
04-24-2014, 10:01 PM
PAR meters do not accurately measure LED intensity for a comparison to MH/T5 - it has an issue with the blue LEDs which are what make up the majority of the LED clusters.

You can actually track this revelation back to Reef Central a few years back - People would build these massive LED arrays trying to get to MH PAR readings and they would have disappointing results from LEDs because of colouration and growth issues. The issue, it turned out, was that they were almost frying corals from the intensity.

People are having better success with LEDs now, because they're putting the appropriate intensities over the tank. If you can't get the PAR readings you want, you may just have to set a low intensity and adjust until you get the results you're looking for. Your corals will let you know.

That really depends on the PAR meter. The meters that us hobbyists usually use (Apogee) are not sensitive to blue wavelengths, and therefore underestimate PAR. Furthermore, the common Apogee sensor is flat, so it only takes into account light coming from directly above the sensor. Spherical sensors, as made by Walz, are more accurate. Licor also makes some highly accurate PAR meters. Unfortunately they are not available to most hobbyists as they are expensive (the Apogee is cheap by PAR meter standards).