PAR measurements

[madweazl]

I thought a database of sorts might be handy for people interested in different lighting setups. 

 

 

 

 

Notes: 

1) Location 3 is centered under one light right to left but not front to back (approx 4" behind the center line front to back). 

2) Locations 6 is very close to the center of the tank (left to right and front to back).

3) The lights are centered over the tank front to back and 15" apart (7.5" left and right of center).

4) The lights are mounted 5" above the water line.

5) There is a fair amount of light spillage on all viewing sides of the aquarium; the lights could be mounted lower to increase PAR values without losing coverage. 

6) PAR values were measured on the clubs MQ-500 with full spectrum sensor using a correction factor of 1.32.

7) Standard 75g Marineland aquarium 48"x18"x21" (LxWxH).

8) Two Kessil A360WE running 65% color.

9) MP40s set to feed mode while measurements were taken. 

Edited June 30, 2017 by madweazl

[Origami]

http://wamas.org/forums/topic/75420-par-meter-results/

 

Over the years, people have posted similar threads and, over ten years ago, there was a spreadsheet with PAR readings from club tanks. That one was really old and, because lighting has changed so much, was unpinned and is somewhere deep in WAMAS's records.  I'll include the link above since it's more recent.

[madweazl]

http://wamas.org/forums/topic/75420-par-meter-results/

 

Over the years, people have posted similar threads and, over ten years ago, there was a spreadsheet with PAR readings from club tanks. That one was really old and, because lighting has changed so much, was unpinned and is somewhere deep in WAMAS's records.  I'll include the link above since it's more recent.

Oops; can we merge the two with the ability to edit the first post and hyperlink to specific lights if/when the thread grows?

[zygote2k]

If you dig deep enough, you'll find where I tested about 8 different tanks with different lighting types and recorded the results.

 

Honestly though, does anyone even care about PAR readings anymore? It's not like anyone is growing corals specifically based upon their demand for a particular PAR value.

[madweazl]

If you dig deep enough, you'll find where I tested about 8 different tanks with different lighting types and recorded the results.

 

Honestly though, does anyone even care about PAR readings anymore? It's not like anyone is growing corals specifically based upon their demand for a particular PAR value.

I think it's still relevant to everyone looking at purchasing or transitioning to a new light. Additionally, if measurements are taken at various intensities you can get an idea of where to start vice guessing where to start. 

[zygote2k]

It's a number value that only provides anecdotal evidence at best. The hobby is full of things like this that provide no real conclusive data, but it does provide a number and measures something, so it must be good, right?

I was once caught up in the PAR measurements but without an actual guide to placement and par values for a given coral, that it amounts to basically nothing.

Watt output is a better numerical value to start with and evaluate light output.

[madweazl]

It's a number value that only provides anecdotal evidence at best. The hobby is full of things like this that provide no real conclusive data, but it does provide a number and measures something, so it must be good, right?

I was once caught up in the PAR measurements but without an actual guide to placement and par values for a given coral, that it amounts to basically nothing.

Watt output is a better numerical value to start with and evaluate light output.

 

In your example, how is evaluating watts any different than PAR? Do 150w MH, 150w T5s, and 150w LEDs produce the same PAR? 

[zygote2k]

Throw par away and just focus on wattage of the fixture. The old rule of thumb was 1 watt per gallon for low light corals, 3wpg for a mixed reef and 5+wpg for SPS.

That was for conventional lights and now that LED has taken over, it's slightly reduced but not by much.

 

When someone can make a guide that says "coral a needs 450 PAR to grow" then I'll start worrying about PAR.

[madweazl]

Someone has 

 

http://www.advancedaquarist.com/2009/2/aafeature1

 

http://www.advancedaquarist.com/2006/1/aafeature1

[AlanM]

I find it useful to take these measurements as a sanity check on how low the PAR is getting as I get down to the bottom.  In the olden days it took lots of heat to get PAR levels high enough to grow hard corals.  It's much easier these days.  Anyone with a couple hundred bucks can grow hard coral.  Now the PAR and spectrum seems to just affect the color, not so much the ability to keep hard corals alive and growing, in my experience.  

 

I find it hard to guess at where "low light" might start by eye.  It all looks bright to me.  The PAR meter is a nice way to measure what I can't judge by eye.

[madweazl]

Took some more measurements with the T5s supplementing the Kessils. 

 

 

Also checked the H80 over the refugium. It produced 132 PAR just under the surface and directly under the light at 100% intensity. 

[sen5241b]

Matching precise PAR to specific corals  is probably a waste of time but completely ignoring it, I think, is also a mistake. Ignore PAR then put acropora under PAR 30 and a funghia under PAR 300. (Don't do that!)

[sethsolomon]

Honestly though, does anyone even care about PAR readings anymore? It's not like anyone is growing corals specifically based upon their demand for a particular PAR value.

 

 

It does matter for some of the reefcrest acros.  Some of them need in the 1k par range to be colored.

[madweazl]

It does matter for some of the reefcrest acros.  Some of them need in the 1k par range to be colored.

 

Do you have any examples of this?

[sethsolomon]

Do you have any examples of this?

Well acropora abrolhosensis, abrotanoides, and robusta all will turn brown/die with under 800 par.  That's why you almost never see them in the hobby.  I have an abrotanoides and a robusta  sitting in the 900-1200 par range and they are staying colored up.

 

 

But ultimately par is only part of the measurement of what light these acros need.  Who knows since LED's measure differently under par maybe 600 all blue par may be the same as 1k par from halides.  As Rob has pointed out Par is mostly anecdotal and we don't really have any scientific data to prove it one way or the other.

[madweazl]

Well acropora abrolhosensis, abrotanoides, and robusta all will turn brown/die with under 800 par.  That's why you almost never see them in the hobby.  I have an abrotanoides and a robusta  sitting in the 900-1200 par range and they are staying colored up.

 

 

But ultimately par is only part of the measurement of what light these acros need.  Who knows since LED's measure differently under par maybe 600 all blue par may be the same as 1k par from halides.  As Rob has pointed out Par is mostly anecdotal and we don't really have any scientific data to prove it one way or the other.

PAR from LEDs isn't any different than any other source. What do you mean by anecdotal and no scientific data to prove it? There is a lot of information on the subject. 

[madweazl]

Was browsing the interwebz and stumbled across a post by Dana Riddle that provided some pretty good data that applied to a monti cap I have. A little over a month ago I had increased the intensity of the Kessils to curb some browning out of one of my acros (ordinarily an intense blue). It colored up rapidly (within a week) but after returning from a work trip about two weeks later, I noticed the monti cap had paled out a bit and was purging zooxanthellae. The Kessils were running at 65% intensity at the time (roughly location "7" in the second chart I posted) which would have put it very close to the photoinhibition point in Dana's post below. I modified the quote to better separate the values (attempted to anyways) and added the * with the full name from the original post in an effort to keep the columns better aligned). The original post can be found here.

 

These values are from various peer-reviewed journals, with a few I did in my lab thrown in for good measure. As a reminder, the 'compensation point' is where enough oxygen is produced by zooxanthellate to meet the respiration requirements of the zoox/host. The 'saturation point' is an estimate of the maximum light requirement. 'Saturation' is when there is too much light and the rate of photosynthesis begins to slow.

Host -- Compensation -- Saturation -- Photoinhibition -- Depth

Acropora cervicornis ------ n/a --281 -- n/a -- 17m
Acropora cervicornis ------ n/a --331 -- n/a -- 17m
Acropora digitifera -------- 82 ---387 --n/a -- 1m
Acropora divaricata --- --- 10 ---77 ----n/a ---40m
Acropora formosa ---------170 --340 --n/a ---1m
Acropora gemmifera ------ 270 - 340 --n/a -- 1m
Acropora granulosa ------- 53 ---102 -- n/a --40m
Acropora microphthalma --- n/a - 300 --n/a --n/a
Acropora millepora ---------- n/a - 190 -- n/a - <2m
Acropora millepora -------- n/a --230 --n/a - <2m
Acropora nobilis ------------n/a --310 -- n/a - <2m
Acropora nobilis ------------n/a --180 -- n/a - <2m
Anthopleura elegantissima ---73 ---n/a ---n/a --n/a
Montipora capitata -------- n/a --135 ---250 - n/a
* Montipora danae ------------ n/a --200 -- n/a - n/a
Montipora tuberculosa ---- n/a --180 -- n/a - <2m
Montipora tuberculosa ---- n/a --300 --n/a --<2m
Pavona varians ----------n/a -- 110 --350 -- n/a
* Pavona/Leptastrea -------n/a-- n/a-- 500 -- n/a
Pocillopora damicornis ----n/a -- 225 --n/a -- <2m
Pocillopora eydouxi --------n/a -- 323 --n/a -- n/a
Porites cylindrica ---------- n/a -- 200 - n/a -- n/a
Porites lobata ---------------n/a -- 250 - 350 -- n/a
Porites lutea ---------------- n/a -- 400 - 750 -- 1.5m
Sinularia densa ------------ n/a -~207 --n/a -- n/a
Stylophora pistillata --------- 40 ----200 - n/a -- n/a
Stylophora pistillata --------- n/a ---300 - 600 --n/a
Tridacna maxima ------------n/a- >600 >1,900 n/a

 

* Monti danae "Superman"

* Pevona/Leptastria "Jack-O-Lantern"

 

 

 

 

[madweazl]

Tested the Aquatic Life Hybrid with two Kessil A360WEs today.

 

 

Notes:

1) Location 3 is centered under one light right to left but not front to back (even with top of rocks on the back side of these two corals).

2) Locations 6 is very close to the center of the tank left to right (a couple inches closer to the front glass front to back).

3) The Kessils are centered over the tank front to back and 18.5" apart (9.25" left and right of center).

4) The fixture is mounted 6" above the water line.

5) There is a bit of light spillage on all viewing sides of the aquarium so the lights could be mounted closer to the water to increase PAR values without losing coverage.

6) PAR values were measured on our local clubs Apogee MQ-500 with full spectrum sensor using an immersion correction factor of 1.32.

7) Standard 75g Marineland aquarium 48"x18"x21" (LxWxH).

8) Two Kessil A360WE (60% color) with four 54w T5s in a 48" Aquatic Life Hybrid fixture (2 Blue+, 1 AquaBlue Special, and 1 Purple+)

9) 16" side rails mounted on the Aquatic Life to narrow the unit 2" from how it ships.

10) MP40s set to feed mode while measurements were taken.

11) Return from sump remained on but has fairly low flow and doesn't agitate water surface much.

12) Hybrid column represents the Aquatic Life fixture with only the T5 on.

13) LET column represents past results of the LET T5 retrofit kit for comparison.

14) The LET retrofit had two 54w T5s (1 Blue+ and 1 Coral+ at the time).

Edited July 29, 2018 by madweazl

[madweazl]

Too late to edit the post but after averaging the nine data points shared between the Aquatic Life fixture and the LET retrofit, the Aquatic Life produced 68% more PAR. That was a bit disappointing given it's running twice as many bulbs (four vs two) but the aquascape is a bit different after the move and the fixture is mounted an inch higher certainly had an impact on PAR levels. 

[madweazl]

Was bored this afternoon so I tossed four A360WEs over the 150g and took some measurements with a Seneye. The Kessils are mounted 9" off the water and 12" on center; the tank is a standard 150g measuring 60x24x24. Kessils were set (manually) to 50% color and 100% intensity. The sand is bed sits an average of 18" below the water surface (water level is approximately 2" lower than if were running normally). I'd expect a 100 PAR increase across the board if the lights were hung 5" off the water. Pumps were turned off while the measurements were being taken.