AquaIllumination PAR Measurements

[jdg]

Originally Posted by CalmSeasQuest

+1 on the PAR meter jdg

For reasons that have been well "illuminated" throughout this thread - To the human eye, LEDs at equal PAR will appear much less bright than MH or T5s. This is the trap so many (including me, multiple times ) fall into that results in tanks being bleached. Trying to match the "appearance" of prior MH/T5 setups results in a significant increase in the PAR.

This of course assumes your lights are functioning correctly.

I'm going to check with my local club and see if anyone has a PAR meter they can lend me. If not, what is a good meter to purchase?

[CalmSeasQuest]

Originally Posted by jdg

I'm going to check with my local club and see if anyone has a PAR meter they can lend me. If not, what is a good meter to purchase?

I think many of us are using the Apogee MQ-200. Hopefully you can borrow one locally - If I recall correctly, I think I paid about $325 about a year ago.

[jdg]

Originally Posted by CalmSeasQuest

I think many of us are using the Apogee MQ-200. Hopefully you can borrow one locally - If I recall correctly, I think I paid about $325 about a year ago.

Thanks! Are you setup with electronic or sun calibration on it? I've seen many references to use electronic, but I also saw a thread from one of their engineers that sun better reflects the true PAR readings of LED's since it will compensate for the underestimation of the blue/red spectrum.

[jdg]

Okay, so I got my hands on a PAR meter and I found that I'm getting about 250 PAR down the center of the tank at 12" depth. I'm getting about 150 PAR on the fringes of the tank, also at 12" depth.

Here's something curious -- one of my new acro frags is starting to receed from the base up, and moreso on the 'light side' that the 'glass side'. PAR at the coral is only 150 ... could that be causing it to receed like that? This is a coral that was under 400 watt 20k MH's. I can't imagine I'm overexposing it at only 150 PAR.

Any suggestions?

[stpatrick]

Originally Posted by jdg

Okay, so I got my hands on a PAR meter and I found that I'm getting about 250 PAR down the center of the tank at 12" depth. I'm getting about 150 PAR on the fringes of the tank, also at 12" depth.

Here's something curious -- one of my new acro frags is starting to receed from the base up, and moreso on the 'light side' that the 'glass side'. PAR at the coral is only 150 ... could that be causing it to receed like that? This is a coral that was under 400 watt 20k MH's. I can't imagine I'm overexposing it at only 150 PAR.

Any suggestions?

What are your setting?

[jdg]

Originally Posted by stpatrick

What are your setting?

75/80/85 on the AI's

[jdg]

Originally Posted by Captain Squid

Your post is in violation of the terms and conditions of use of this web site and has been edited. Further violations will result in revocation of your posting privileges.

But that is what is strange, I'm getting more STN on the side facing the light. The side facing the outside of the tank/glass is in better shape. It's like the "shadowed" areas are doing better. To me, I would think it was getting too much light -- but at 150 PAR? How could that be?

Plus, they've browned out and polyp's are not extending. I would figure excess light wouldn't brown them first.

[CalmSeasQuest]

Originally Posted by Captain Squid

They are starving for light!

Doubtful.

You typically don't see immediate RTN when exposed to lower PAR. Conversely, I have had SPS suffer RTN even at lower PAR values if they receive rapid, large % increases. It would be good to know how much PAR it was getting before.

The fact that only the bright side is RTN'ng is potentially telling. Also that it's a new frag. Any signs of problems with anything else?

This of course excludes any other environmental issues or changes.

[stevedola]

its getting fried! move it down or try and lower your light intensity. I went from 350 par to 250 par and still fried some peices. LED light is different and corals need to adjust.

[jdg]

Originally Posted by stevedola

its getting fried! move it down or try and lower your light intensity. I went from 350 par to 250 par and still fried some peices. LED light is different and corals need to adjust.

Will it brown out if light is too intense?

Polyp extension is very poor as well -- is this also symptomatic of too much light?

[jdg]

Originally Posted by CalmSeasQuest

Doubtful.

You typically don't see immediate RTN when exposed to lower PAR. Conversely, I have had SPS suffer RTN even at lower PAR values if they receive rapid, large % increases. It would be good to know how much PAR it was getting before.

The fact that only the bright side is RTN'ng is potentially telling. Also that it's a new frag. Any signs of problems with anything else?

This of course excludes any other environmental issues or changes.

I agree that it was odd that only the 'bright side' was STN'ing but the whole piece was browning out. No other issues with anything else other than some new GSP's someone gave me.

SG is 1.025
Ca is 450ppm
ALK is 10 dKh
PH is 8.3
Mg is 1300ppm
PO4: undetectable, low range
NO3: undetectable

Temp is pretty stable, between 78.1F and 78.8F

I'm running an ATB Medium Skimmer, BioPellets in an Octopus BR140, Chaeto in a fuge.

[hollywood85]

Any sps acclimating advice anyone can give me? Getting my first frags today since the change over. All existing sps is doing great. Just wondering of any experiences? Thanks

[JAGreef]

I am still having a difficult time keeping "new" frags from friends that had the frags under 250 - 400 W Metal Halides. My current setting is 40-50-50 (w-blu- royblu) for most of the day with a peak of 50-65-65 for about 4 hours in the middle of the day cycle.

The frags seem to do well the first day but then go brown then rtn over the next week....

Do I need to scale back the intensity every time I introduce a new frag or just place it on the sand then slowly bring it up over a few weeks? Or are my settings to low?

My stats:
72x18x24
4 AI's on an Apex controller
pH=8.1
Calc=440
Alk = 11
mag= 1450
salinity = 1.025
temp= 78.5 to 80
phos & nitrate = non-detectable

[jdg]

Originally Posted by JAGreef

I am still having a difficult time keeping "new" frags from friends that had the frags under 250 - 400 W Metal Halides. My current setting is 40-50-50 (w-blu- royblu) for most of the day with a peak of 50-65-65 for about 4 hours in the middle of the day cycle.

The frags seem to do well the first day but then go brown then rtn over the next week....

Do I need to scale back the intensity every time I introduce a new frag or just place it on the sand then slowly bring it up over a few weeks? Or are my settings to low?

My stats:
72x18x24
4 AI's on an Apex controller
pH=8.1
Calc=440
Alk = 11
mag= 1450
salinity = 1.025
temp= 78.5 to 80
phos & nitrate = non-detectable

Similar issue here ... new frags have a really tough time. They brown out, and then STN, usually from the base. How much PAR are you getting at the frags? I'm only getting 150 or so. How high are the lights off the water? Standard optics or all 40's ?

I'm at 12" AWL and running 65-70-75 peak.

I don't understand how LED PAR is somehow different than T5 PAR or MH PAR ... isn't that the point of measuring PAR? Because it's consistent against the different light sources?

I also don't understand how a frag kept under 400W MH is going to get too much light from an AI unit at 150 PAR.

[RocketSurgeon]

Originally Posted by jdg

Similar issue here ... new frags have a really tough time. They brown out, and then STN, usually from the base. How much PAR are you getting at the frags? I'm only getting 150 or so. How high are the lights off the water? Standard optics or all 40's ?

I'm at 12" AWL and running 65-70-75 peak.

I don't understand how LED PAR is somehow different than T5 PAR or MH PAR ... isn't that the point of measuring PAR? Because it's consistent against the different light sources?

I also don't understand how a frag kept under 400W MH is going to get too much light from an AI unit at 150 PAR.

There is a difference between PAR and PUR. This may be the difference you are seeing.

[jdg]

Originally Posted by RocketSurgeon

There is a difference between PAR and PUR. This may be the difference you are seeing.

What's the difference? Do you have any links that explain?

Using a PAR meter, I thought it would come out the same regardless of the source.

[RocketSurgeon]

The par may com out the same. But the PUR will be different. I can look up sources that explain the difference of the two. The "U" in PUR stands for "Useable".

Try this tidbit of info:

http://www.athiel.com/lib5/parpur.htm

I'll look for my original source after lunch.

[jdg]

Originally Posted by RocketSurgeon

The par may com out the same. But the PUR will be different. I can look up sources that explain the difference of the two. The "U" in PUR stands for "Useable".

Try this tidbit of info:

http://www.athiel.com/lib5/parpur.htm

I'll look for my original source after lunch.

Thanks !

[RocketSurgeon]

Below is copied from:

http://www.marshreef.com/modules.php...r+pur&start=15

"I see what you are saying about the RB and PAR. I was just trying to clarify that PAR readings are an average of light measured between 400 and 700 nm. Therefore since RB is only between 440-480nm it has a low PAR. That is why PAR meters show very low readings on RB. However they have a lot of PUR (Useable) in one of the 3 necessary spectral bands necessary for corals to thrive. This is especially true for deepwater corals. But to be clear, it would be very difficult to grow coral with RB only whereas you can grow coral on only CW. This is because you also need light in the 670nm (red) area of the spectrum. So you cannot compare RB to CW in the ability to grow coral. But you can have even better growth with RB and CW. "


Let me say, I don't know enough to explain, but...
Different coral need different light spectrum to grow. Before, we used MH's as a shotgun approach (broad range of spectrums) to feed the coral. With LED's, It may be possible that you can separate the color spectrums based upon what each coral needs.

Maybe someone with more knowledge can steer us both in the right direction.

[RocketSurgeon]

http://www.americanaquariumproducts...._Lighting.html

I believe the above link is what I was looking for. I don't know the accuracy of the article.

Below excerpt is copied from above link:

"PUR (Photosynthetically Usable Radiation) also known as "Useful Light Energy" is what concerns us as aquarium keepers even more than PAR in providing correct lighting (yet provides a lot of confusion, especially when considering LED Lights).
PUR is that fraction of PAR that is absorbed by zooxanthellae photopigments thereby stimulating photosynthesis. As noted above, PUR are those wavelengths falling between 400-550nm and 620-740nm."

[jdg]

Originally Posted by RocketSurgeon

http://www.americanaquariumproducts...._Lighting.html

I believe the above link is what I was looking for. I don't know the accuracy of the article.

Below excerpt is copied from above link:

"PUR (Photosynthetically Usable Radiation) also known as "Useful Light Energy" is what concerns us as aquarium keepers even more than PAR in providing correct lighting (yet provides a lot of confusion, especially when considering LED Lights).
PUR is that fraction of PAR that is absorbed by zooxanthellae photopigments thereby stimulating photosynthesis. As noted above, PUR are those wavelengths falling between 400-550nm and 620-740nm."

But PUR is a fraction of PAR ... so wouldn't an MH producing a PAR of 450 still be stronger than an LED producing a PAR of 150 regardless of PUR ?

[RocketSurgeon]

Originally Posted by jdg

But PUR is a fraction of PAR ... so wouldn't an MH producing a PAR of 450 still be stronger than an LED producing a PAR of 150 regardless of PUR ?

But the MH (450 par) has a PUR of 125, while the LED (150 par) has a PUR of 150. Because we can pick and choose which color of LED light we want, we can alter our PUR numbers. With MH, we have less ability to change the colors. Now, I just pulled these numbers out of thin air, as an example.

[RocketSurgeon]

Sorry to get off the original quest of the thread...

Here is another article concerning LED's. I'm sure this is biased a bit, as it is trying to sell their product.

http://orphek.com/wordpress/about/

Below is copied from above link:

"Unlike the less than optimal spectral curve, wasted energy and inferior color rendering of Cree and other emitters, our diodes are truly full spectrum with high Kelvin and CRI ratings and emit an efficient and high-PUR spectral curve for photosynthetic organisms. "

[jdg]

Originally Posted by RocketSurgeon

But the MH (450 par) has a PUR of 125, while the LED (150 par) has a PUR of 150. Because we can pick and choose which color of LED light we want, we can alter our PUR numbers. With MH, we have less ability to change the colors. Now, I just pulled these numbers out of thin air, as an example.

That would make sense, but I didn't expect that the PUR would be some a small percentage of MH PAR.

[JAGreef]

So unless there is an accurate correlation between the 2, we will need to rely on our fellow reefers to provide some guidance based on their experience. With that in mind, what experience is out there to provide guidance on how to better acclimate "new" frags into my system when the frags are coming from 250-400 MH systems to my AI LEDs (~10" AWL- all 70 deg)?