LED Measurement Equipment

[Ryan115]

I finally have my LEDs up and running on the tank. Before I start stocking corals I would like to get the color and more importantly the output dialed in to a target range.

To avoid going off topic, I will keep the brand unlisted for now, as settings should be tailored to each tank/light setup. Also please lets ignore any vendor provided presets for the time being as I feel even those should be checked on each system.

I have seen a wide range of options for a variety of metrics (PAR, lux, spectrum, etc...) ranging from high-end lab grade sensors down to phone apps using integrated luminosity sensors.
Each has it's uses, and its target users. Some people want to know the lights down to the μmol/m^2/s and some just want to know if they have enough light to grow/not bleach coral. Then there are those that want the former, but can afford the later.

My goal is to get a moderately comprehensive list of the typical options a reefer has.
Looking around, the information seems to be spread through a multitude of posts, but if a chart or list already exists please point me to it.
I would like to hear opinions and experiences on what people have used and how they compare to other units.
Bonus points for comparison and/or calibration factors of high end to low/no cost sensors.

 

[saltyfilmfolks]

A lux meter measures light intensity.

A par meter measures the intensity of the light most closely associated with photo synthesis. So spectrum +intensity

A spectrometer will let you see the mixture of the spectrum. This will let you identify the Nm of light that may not be desirable for coral and adjust the spectrum to blend a color temp that Is pleasing and grows corals best.

Those are the basic tools.

 

[Ryan115]

Thanks salty. I should have guessed you would have been first on this.
I understand the different sensors and their general use, though with the control-ability of LEDs some of this information would be very helpful to people changing over or starting with LEDs. If it is already in a sticky, I missed it.

However trying to look more at the specifics about the different brands and units.
I know many of the PAR sensors are more geared to terrestrial plants and/or phytoplankton, so more of a mapped response for Ch-A & B.

I guess starting with the basic tool that most everyone has, a smart phone.
Is there any methods to calibrate your phone to get useful data out of the built in sensors?
How useful is the internal sensor for most phones? I have not seen a responsivity chart for a phone sensor to know what it would even be reading from. As many of the LED fixtures are starting to push both ends of the spectrum, If the sensors are weighted for a human eye response, are the down-playing the abundant blues and violets in most lights?
Either way, most information available is on PAR levels (and could be argued either way which is more relevant) but are there any guidelines for target lux levels (which I guess would depend heavily on spectrum as well, since we would just be measuring photons)

My main goal is to at least get someone in the ball park that is setting up lights, but doesn't have access to or funds for a real meter.
Will something like a LX1010B or LX1330B be much better than a phone? Some of the charts I have seen for those look like the really drop off below ~550nm.

 

[saltyfilmfolks]

It's a phone , sorry, Camera. I'll leave it there.

Those three tools are really what you need.

An apogee par meter is a lux meter.
It's a photo cell. A highly sensitive one. Then there are three gels. R g b

Each color filter lets a specific NM range through it. R G B we know has a range of NM.

Then in the par meter there is a disk with holes in it. Each of a different size. The color with the most lest the most light though.
Those are R and B

From that the sensor creates electricity. Based on that amount the needle moves.

Becuse there is r g b this is why it reads terrestrial light. It's reading R (actually r y o). In theory you could recalibrate the meter with a disk that limits the R yo range and it would be more suited for marine light.
This I belive is how the pur function works on the seneye btw. But that uses software and a different sensor type.

So par meters are really only giving us a base line intensity kinda. But if all the P A R on the planet. It's averaging each color range becuse it only has one photocell.

If you had one photo cell per color the needle would move independently and give you more of an idea of the ratios in the light and you could assign a value to that depending on the amount , Esp in the R B range. This value would be cooler temprature. And the three sensor machine would be a color temp meter. OR camera

To see the more minor differences in each R G B range and see the balances of the peaks (Like the spectrum graph when buying a new light ) then, you have to break each one down into individual NM. That tool is a spectrometer. Also a Prisim.

The difficulty with a prisim or hobby spectrometer (like mine for kids ,no really it does work) s getting the array to blend correctly and most importantly blend fully. But you can look at an individual diode , t5 , or mh. Just wear eye protection to anyone reading this. You can cause permanent damage.
Like mine.

The prob with the color meter, if one spectrum is way too high in intensity compared to the rest (blue for us) it overloads the sensor and gives error readings or blows up the software trying to balance them. (Auto white balance) Thats also why blue pictures are so blown up with you're camera.

Even worse, your pictures are blown up , but your wife's new iPhone aren't. It's sensors have a broader range in each RGB.
And that's why hard to use a phone for a par meter. Each phone/camera/sensor have different ranges.

 

[Ryan115]

Thanks for all of the info Salty.
Actually I didn't even think about the fact that they were using the camera as the light sensor on the phones. Completely makes sense though.

So are their any methods that you know of for getting a LED system in the ball park, without spending hundreds on test equipment that most people wont use again?

I do have a TAOS TSL2561 for some underwater ambient light readings at depth, that I can use for this.
But then again, most people likely wont be interested in a DIY approach.

 

[Newb73]

1) May i ask why you wouldn't be interested in something like the AB settings by Ecotech/BRS settings?
2) Disagree that you will only use a par meter once. I use mine about as often as i use my refractometer and way more than my hannah phosphate checker.

It helps me figure out where to put corals, whats goin on in shaded areas, you can even ise it to tell you if a light went out/got left on or the carbon needs changing (in the case of a pmk).

.

 

[Ryan115]

1) May i ask why you wouldn't be interested in something like the AB settings by Ecotech/BRS settings?
2) Disagree that you will only use a par meter once. I use mine about as often as i use my refractometer and way more than my hannah phosphate checker.

It helps me figure out where to put corals, whats goin on in shaded areas, you can even ise it to tell you if a light went out/got left on or the carbon needs changing (in the case of a pmk).

.

The main reason I wasnt wanting to get into any pre-sets is they they are specific to that particular light, and I am looking at across-the-board LED setup equipment.

The PMK is something that can work for those already with an Apex, but will not appeal to everyone.
Some people want to set it and forget it and others want to consistently tweak the system. Each method has its own pro's and con's.

I am a full believer in LEDs, however I see alot of people that are dissapointed with them, be that from improper initial setup or from "playing" with them too much for their corals to tolerate.
What I am trying to get to is a simple approach that someone can start with to get them in the ball park and in the right direction.

A high additional cost for a sensor will surely dissuade some people from LED and push them back to "known" values of a Halide or T5 setup.
Though one could argue that a light measurement could be more useful there, for diagnosing aging bulbs output and spectrum shift

 

[Newb73]

The main reason I wasnt wanting to get into any pre-sets is they they are specific to that particular light, and I am looking at across-the-board LED setup equipment.

The PMK is something that can work for those already with an Apex, but will not appeal to everyone.
Some people want to set it and forget it and others want to consistently tweak the system. Each method has its own pro's and con's.

I am a full believer in LEDs, however I see alot of people that are dissapointed with them, be that from improper initial setup or from "playing" with them too much for their corals to tolerate.
What I am trying to get to is a simple approach that someone can start with to get them in the ball park and in the right direction.

A high additional cost for a sensor will surely dissuade some people from LED and push them back to "known" values of a Halide or T5 setup.
Though one could argue that a light measurement could be more useful there, for diagnosing aging bulbs output and spectrum shift

We agree.

I realized just how woefully under effective the minimal manufacturer's recommendations are for good coverage and par.

I now have 7 LED fixtures on a 6 ft tank....

It also seems LEDs are more prone to hot and cold spots meaning you really do need a par meter.

This translated into the true cost of LEDs being much higher than advertised.

I still prefer them for aesthetics, features, control, power consumption and longevity/low main though.

 

[saltyfilmfolks]

Thanks for all of the info Salty.
Actually I didn't even think about the fact that they were using the camera as the light sensor on the phones. Completely makes sense though.

So are their any methods that you know of for getting a LED system in the ball park, without spending hundreds on test equipment that most people wont use again?

I do have a TAOS TSL2561 for some underwater ambient light readings at depth, that I can use for this.
But then again, most people likely wont be interested in a DIY approach.

Having said all that above , if you are confident your light has the spectrum required to both grow coral and make viewing pleasant, you can now only test intensity and search for the level that works best for your tank. The "sweet spot".

The sweet spot is determined by a few factors , alk and Nutrients being the most well known.

 

[saltyfilmfolks]

1) May i ask why you wouldn't be interested in something like the AB settings by Ecotech/BRS settings?
2) Disagree that you will only use a par meter once. I use mine about as often as i use my refractometer and way more than my hannah phosphate checker.

It helps me figure out where to put corals, whats goin on in shaded areas, you can even ise it to tell you if a light went out/got left on or the carbon needs changing (in the case of a pmk).

.

You both have really valid points. Good talk.

My observation of each of us we've developed a comfortable method of doing the exact same thing.

But with led, I never test anything. Honestly I test alk and salinity.
I don't test what I'm not going to change. If I'm acclimating a tank. Yea, I use the meter and tests to increase or decrease a value.

When changing a spectrum howver. A par meter is kinda useless in a way , unless you understand spectrum already. And that adding "white" increases par, but you really need to know why, and whats in white.

I will bring up a fairly interesting pont, with a t5 it's a field of light with an even falloff, and only wore sand and the color of the rock effecting reflectance an increasing par. . . With pucks, yep hot spots.

One I have identified the hot spots, I don't test again. I also know that one the coral is acclimated to the spectrum in my tank, moving a coral 50-100 par does not make substantial difference. That's IME.

And yea. Leds at suffering the rush to market problem.

To stop the hot spots, I did this.
3 lights and diffusion. My settings are 30% white and 1% blue.

(Cuz if I didn't have a meter I wouldn't know that 1% is actually 300par at the top of the tank)

 

[Ryan115]

Salty,
I think I saw in another post where you had some ball park "conversions" from lux to par (I know it isnt really), or at least a target range that you shoot for.
If so, could you re-post them.

You are all over the forum, so I can even think about searching though a few thousand of your posts for what I am talking about.
Thanks.

 

[oreo54]

LUX divided by 69 or 70-ish..
some others for comparison:
https://www.apogeeinstruments.com/conversion-ppf-to-lux/
http://agi32.com/blog/2014/12/10/photometry-and-photosynthesis/
The more blue the less accurate..

 

[saltyfilmfolks]

Salty,
I think I saw in another post where you had some ball park "conversions" from lux to par (I know it isnt really), or at least a target range that you shoot for.
If so, could you re-post them.

You are all over the forum, so I can even think about searching though a few thousand of your posts for what I am talking about.
Thanks.

Hahahaha. Yea it gets like that.
I'll do you one better than listening to my drivel.

Mr Riddle.
http://www.advancedaquarist.com/2013/2/equipment

In short , deviding lux by 60 comes pretty close with an led of the 14ooo to 20,000. + kelvin range (see article on why)

That makes 100 par about 6000lux.

Look at your tank and only think in par. What coral goes at the top? How much par do you think you you want there?
If it were a par meter you would do the same.

So a guess on a high light tank with 200 par on the bottom and 600 par on the top would be around ........lux. (You do the math there)


Also, maybe ask santa for a seney meter. A decent $15 lux meter(white disk incedent ) is a great stocking stuffer. A welders glass and a $5 spectrometer is good learning tool.

 

[saltyfilmfolks]

LUX divided by 69 or 70-ish..
some others for comparison:
https://www.apogeeinstruments.com/conversion-ppf-to-lux/
http://agi32.com/blog/2014/12/10/photometry-and-photosynthesis/
The more blue the less accurate..

Good post and links. The higher the blue the the higher the conversion constant.

Only by observation and testing and manufacturer specs, did I come by the number 60. A max razor is 60. A mars aqua solidly comes out at 63.

When I eastimate , I then do the rest of the math.
Ie devide by , 60 , 65, 70. It'll show you the range and how kinda insignificantly small the difference is.