URS PAR reading picture thread

[Gary Majchrzak]

those that have used the Apogee meter please post your results to this thread

for those unaware what PAR is

<a href=showthread.php?s=&postid=9760036#post9760036 target=_blank>Originally posted</a> by Sanjay
PAR stands for Photosynthetically Available Radiation. Radiation that is in the 400-700nm range. It can be measured as energy (Watts/m^2) or as Photosynthetic Photon Flux Density (PPFD) where the units are micromoles of photons/m^2/sec.
Your quantum meter from Apogee is measuring PAR as PPFD in units of micromoles/m^2/sec.

left side: 250w Hamilton 10k on EVC eballast
center: 400w Hamilton 14k on Blueline eballast
right side: 250w Hamilton 10k on Blueline eballast

two 6 ft. long VHO actinics were on when these readings were taken

 

[rjrobert]

I would love to do something similar. I've got 3 400w 10ks and 6 96w PC actinics. I would love to see how the light diminishes. Does someone in the club have a PAR meter that they lend or rent out?

 

[MarkKlier]

We are currently cycling it through URSNY. As we get through that I would anticipate that we will set up a system that people in URS can participate in this. Will keep you posted.
MK

 

[suppressivefire]

<a href=showthread.php?s=&postid=11003304#post11003304 target=_blank>Originally posted</a> by rjrobert
I would love to do something similar. I've got 3 400w 10ks and 6 96w PC actinics. I would love to see how the light diminishes. Does someone in the club have a PAR meter that they lend or rent out?

I second that question.

 

[Gary Majchrzak]

PCIALF's PAR readings (as posted on the URSNY site)

Aqualight Pro w/ 2 hqi 10k 150's and 2 96w 420 actinics

FWIW: this is a very impressive aquarium to see in person.

 

[RCBrooke]

Cool Gary! Any idea what number would be too much light?

Randy

 

[Gary Majchrzak]

<a href=showthread.php?s=&postid=11016069#post11016069 target=_blank>Originally posted</a> by RCBrooke
Cool Gary! Any idea what number would be too much light?

Randy

I think the meter only goes up to 2,000 micromoles/m^2/sec.
(I've only seen the Apogee max out under full sun on a clear day.)
Of course, if you're referring to what would be to much light for a reef aquarium it all depends on what you're keeping in it. Not all corals thrive under the same light intensities/ environmental conditions.

 

[KurtsReef]

Bring it by with my sign up sheet for the URSNY

 

[RCBrooke]

Details, Pesky little details Gary ... LOL.

To be a just "little" more precise: say on your tank as stocked, what level do you believe would start to be a concern to you. Just trying to get a loose / relative idea of how the numbers range. Oh ya, talking corals only here.

Probably still to many variables but just take a w.a.g. if you wouldn't mind.

Thanks.

 

[fat-tony]

read the thead that stevel posted a while back from MACNA. there's some info on what corals need what light to thrive. you'll be surprised what you see

 

[RCBrooke]

Thanks Jason, I'll see if I can find it.

Randy

 

[RCBrooke]

So much for the easy route - not on a pages still up. I'll try the search function again later.

 

[fat-tony]

Dana Riddle â€"œ Coral Coloration


Typical tropical sun @ 2,100 umol.m2.sec max PAR @ noon
Typical SPS aquarium 233 umol.m2.sec

Reported data from PAM on ETR rates with on-set of photosaturation, saturation and photo-inhibition. Thought provoking presentation but I question data because fact that corals can/may be able to photoadapt would undermine the results. Not sure what conclusions can or should be drawn from this data other than we can overlight our tanks with MH lighting. Worth studying Dana’s data on pigment absorption spectra. Photo-adaption studies need to be done.

From stevel's post

The highest light (400 before saturation occured) required were by some blut tort species with many of the red's coming much lower (under 200)

that's if i remember correctly

 

[RCBrooke]

Thanks. Hum.... So does Gary's reading of 600 micromoles at the top coal/rock suggest light Saturation underneath the middle light (400w MH)? Or have I got The units mixed up?

 

[fat-tony]

according to the presentation, it looks like he's got the right coral in the right spot. at the saturation point photosynthesis still occurs, but is on it's downslope so not much harm in it...if any

 

[RCBrooke]

Great info.

For some reason I thought that corals bleached at the saturation point. Is there a term for so much light a coral bleaches? And for a high light SPS, where would you "estimate/guess" the bleaching point to be? At the 2100 umol Tropical Sun at noon level?

Thanks a lot.

 

[fat-tony]

i wouldn't even dare guess on the bleaching (i think more than light is responsible in most cases anyways). saturation is just the point when photosynthesis is at it's max.

again, just what i remember off the top of my head.

 

[RCBrooke]

The reason I asked about light and bleaching is that I saw a statement on a site about corals being grown under 1000w MH's. Seemed like enough light to fry bacon.

Great info. Guess I'll call it quits.

Thanks again Jason

 

[fat-tony]

usually with that much light there's a ton of depth to go through. the top part of the water may have issues but as you go further down light drops off quickly

 

[Gary Majchrzak]

<a href=showthread.php?s=&postid=11016230#post11016230 target=_blank>Originally posted</a> by RCBrooke
Details, Pesky little details Gary ... LOL.

To be a just "little" more precise: say on your tank as stocked, what level do you believe would start to be a concern to you. Just trying to get a loose / relative idea of how the numbers range. Oh ya, talking corals only here.

Probably still to many variables but just take a w.a.g. if you wouldn't mind.

Thanks.

2,000 micromoles/m^2/sec would only be realized in nature. Even greenhouse growout systems (at the very surface of the water) don't receive this much PAR. Some shallow water species of Acropora routinely get exposed to full noon day sun at low tide in the wild. Taking all of this into account I don't believe that artificial lighting can produce enough PAR to concern me the way my aquarium is stocked (shallow water/ high impact zone).
That being said, I do feel that three 1,000 watt halides over my aquarium would be "overkill".
Corals can thrive in captivity without receiving the maximum PAR they can tolerate.