Best Par Meter For LED lights

[Russ265]

I just downloaded the Light/Lux Meter free App and got a reading of 208,234 on my Orphek LEDs. Hmmm something seems a little "fishy"

maybe the sun cc'd you too

orphek cant break 1k par on any of their products

 

[mcarroll]

my leds put off more power than the sun

Well, 1100 PAR is about 50% of direct sunlight levels.

But I think that 180,000 lux reading of sunlight is incorrect. Try reading sunlight reflecting off a plain white sheet of paper and see what you get. I'd just try a different app if that is concerning.

Most of the apps I've seen appear to be made (and probably calibrated for) for indoor levels....so yours might simply be exceeding the app's range in sampling the sun.

The lux reading of your light looks to be correct though... 1100 PAR (@1") * 50 = 55,000 lux....dang close to 65,000 lux you pulled at the surface!

Rather than stridently assigning value to specific lighting levels or to particular ways of measuring light as "best", it's far more useful (IMO) for us to be aware of actual real life light intensity levels, light compensation points as well as intensity levels that others have succeeded with - and to have a solid idea of your own light's intensity by way of a light meter you can afford. I think that starts with a free or $15 lux meter for most people....but it doesn't have to end there if a PAR meter is judged necessary. Upgrade!

Dana Riddle (one of my lighting heroes) might have said it best in this article:

Many use lux meters for measuring light and although these are better than not taking measurements at all, the preferred method is using a quantum meter (although see 'Converting Lux to PAR' section later in this article). Lux meters are generally less expensive than PAR meters.

You'll notice he doesn't bother telling anyone lux meters are inferior to the task or the least bit useless - even though it would be germane to the article. Instead he gives tips for usage. This article is where I got the idea in the first place.

most popular number ive seen is to divide by 76.

Dana posted a limited list of conversion factors in that article. "76" seems arbitrary - equal to a warm white florescent light - not necessarily a good average or representation.

I stick with the conversion factor of 50 because A: it works for me every time so far, and B: it's close to the conversion factor for sunlight so I see it as more universal. (Okay, C: it's also a lot easier to multiply and divide by 50.)

If you know off-hand: how many watts do your lights consume at the wall? I'm curious about your watts per square inch or meter.

I just downloaded the Light/Lux Meter free App and got a reading of 208,234

Try a different app. If you happen to be on IOS, "Galactica luxmeter" seems to get good results. There are others on Android too though.

The light meter on a camera is not the same kind of light meter as we'd use so software interpolation is required to get a good number....and apparently not all apps work equally well with all cameras, so you can get mixed results. A different app should work better....I don't remember anyone going away without finding an app that worked well enough to get them started.

This is why I generally tell people to start with the $free app, but while it's downloading to go and order a $15 handheld....the handhelds are much better, not to mention safer around your tank than a $600 smartphone.

I'm interested in trying a lux meter. The only thing that confuses me....we know what par level coral X needs, eg: sps at 400-450 par.

Without converting Lux to par, how do we use the numbers on the meter if they really don't tell me anything? Or unless there's a "lux range" for sps, softies, etc. From point #3, would you imply that sps would need 40-50k lux?

There're a couple of ways to answer that.

One, just use a conversion factor of 50. If you are talking about 500 PAR, then you're talking about 25,000 lux. Simple.

Two: Read above....species of coral do not require any specific light levels. It's significantly more complex than that, involving the type of zooxanthellae present, nutrient levels, water flow, coral species, etc....don't confuse your light setup with all these matters.

The only time specific light levels practically come up is when you are moving established colonies. Moving them to a very different light environment (brighter or dimmer, in fact) can be deadly. So taking lux (or PAR) readings of the old light setup and making sure the new light setup duplicates them fairly close is crucial.

Frags, by comparison, are very adaptable. So starting a tank from scratch (and frags) allows you quite a bit of latitude in setting the tank's intensity level. In that scenario, I'd generally shoot for something on the lower end of the scale like 20,000-30,000 lux, but there's nothing magical about that range. 20,000-80,000 should be acceptable for many corals. However, you'll also find people (not just me) keeping stony corals happy with light levels as low as 10,000-15,000 lux or higher than 80,000. Like I said earlier, it's more complicated than just light.

I don't have the links or PDF's handy (@Russ265 by any chance?) but there are one or two PDF's I've posted or linked to before where this complicated situation has been studied and illustrated/explained really well. The best might be the one that questioned whether the relationship between corals and their zooxanthellae is actually symbiotic or not. The other one studies corals repairing tissue and skeletal damage under different light, flow and nutrient scenarios. Stuff I found via scholar.google.com. (Russ is actually even more into this overall nutrient/coral growth scenario than I am...I'm just trying to get everyone to measure their lights ...check out his threads!!!)

 

[saltyfilmfolks]

a true light meter uses a photocell to gauge intensity. lux or foot candle, and a par meter does too. A camera does not, it tries to "interpret" it. it usually does not go well. and , its a phone.
My $15 lux meter works fine, every body should own one. then borrow a par meter.

If I were to buy a par meter it would be the new apogee, please read their white paper on led par readings on thier website. ive seen a couple of seneye results that were way off of what they should be using lux par conversion. WAY OFF.

Dana posted a limited list of conversion factors in that article. "76" seems arbitrary - equal to a warm white florescent light - not necessarily a good average or representation.

I stick with the conversion factor of 50 because A: it works for me every time so far, and B: it's close to the conversion factor for sunlight so I see it as more universal. (Okay, C: it's also a lot easier to multiply and divide by 50.)

google dana Riddle lux par.

the reason a lux meter can be of more use to us is once you know the intensity you can manipulate it and change it. Like knowing DHK or any other parameter
.
if you are getting coral browning because on high nutrients, you can increase the lights from 30,000 lux to 40,000 in two weeks. if you get bleaching you can now back off to 35000. no fake percentage games.
plus if you change lights and need to hang the new one higher you can test it. old light is 30k lux, replace the old one and set the new dimmer at 30klux again(or 20k lux to acclimate).
If you did that with a par meter, you would have to set all intensities and all color(w/b) balances to get the same par. White has higher par in led. if you have three colors or more to set how are you ever gonna guess how you get to 300 par. you can get to 300 par on just one chanell.
set the color to eye and measure the intensity, you can also measure and mark the individual colors percentage that got you there. I do. then you can back off the blues increase the white(or vice versa) and keep the same overall intensity on the tank..

fwiw. a chinese black box mars aqua , from numerous lux and par data i have observed seems to be a constant of 65 at 100% 1to1 ratio on both chanells.. SBreeflights seem to be 60ish but i will need more data.
no idea why mr riddle said 70, it seems like old data on old leds and the article was written many years ago. When I meet him at macna thats the first thing I will ask after I take his drink order.

so it seems 50 or 60 is a good number to use in lux par conversion. folks who say they are getting weird things happening at +- ten par I really have to doubt.

to finish this confusion you will still have to guess as to what the coral likes anyway and still aclimate. add to that I think if you did use a par meter you be surprised because your coral are fine and you either have too much or to little light than is recommended because I have seen some great corals growing in some how does that even work kinda ways. an "sps" is not a high light coral, some are, and zoas grow in tide pools and are exposed to air and full sun, some anyway.

 

[mcarroll]

Thought I had em all in that last entry...

[...]When it comes to plants or coral ....lux is much less useful.[...]PAR meters are still not perfect in this regard but exponentially better than a lux meter.

Have you tried a lux meter app or handheld unit?

What you assert doesn't seem to be the case in my experience, nor the experience of anyone else I've seen use these lux meters.

This also doesn't account for the reality that consumer grade meters aren't that different at all.

Check out the Dana Riddle article I posted prior - it's easy to discover the PAR to lux conversion factor for your light if you have both meters. Using the conversion factor, your lux meter is a near-perfect PAR meter.

You can also find threads on other sites where people have converted one of these handheld lux meters to a PAR meter.

I believe you'd find these articles eye opening.

I am reading around 25k lux mid day above the water on my system. If I crank my LED all the way up it will read around 45k. I notice the white led affects the lux reading the most.

I'm not sure how this translates into par. I don't feel my light is bright enough.

Does anybody else have lux readings from their succesful setups that I could compare to?

First, either of those numbers are great:

25,000 lux ÷ 50 = 500 PAR
45,000 lux ÷ 50 = 900 PAR​

Second, I wouldn't make any drastic changes if you already have corals growing.

Third, check out the info and links I put in my last post. One link is to a search that has actual results people have posted here. You can run the same search for PAR numbers and just convert them to lux by multiplying by 50 (the conversion factor for sunlight).

Just to quickly reiterate in a nutshell, anything from 20,000 lux up to 80,000 lux is likely to be acceptable. Probably lower on the range is better than higher.

 

[saltyfilmfolks]

maybe the sun cc'd you too

orphek cant break 1k par on any of their products

they seem to be of the camp, 400 par on any given coral and above is a waste. Interesting papers on that theory. I havent seen (or come across recent research supporting higher par use. only user data and personal experience.

fwiw. in this useres opinion and experience, My phoenix 14k MH ripped a maxspect and an sbreeflight to shreds with near immediate color and growth results(two weeks in reef in terms) results at the same Lux. better coverage too. at 40,000 lux calc the par on that one.

 

[Russ265]

they seem to be of the camp, 400 par on any given coral and above is a waste. Interesting papers on that theory. I havent seen (or come across recent research supporting higher par use. only user data and personal experience.

fwiw. in this useres opinion and experience, My phoenix 14k MH ripped a maxspect and an sbreeflight to shreds with near immediate color and growth results(two weeks in reef in terms) results at the same Lux. better coverage too. at 40,000 lux calc the par on that one.

i think their data may need to be relooked upon...

https://www.researchgate.net/public...ral_Stylophora_pistillata_as_measured_in_situ

i had phoenix bulbs as well when i ran mh. great bulb and difficult to find an led comparable in performance. im quite happy with the black boxes (as are the thousands using them)

https://m.facebook.com/groups/603511806434292/

 

[LakeCityReefs]

Thought I had em all in that last entry...



Have you tried a lux meter app or handheld unit?

What you assert doesn't seem to be the case in my experience, nor the experience of anyone else I've seen use these lux meters.

This also doesn't account for the reality that consumer grade meters aren't that different at all.

Check out the Dana Riddle article I posted prior - it's easy to discover the PAR to lux conversion factor for your light if you have both meters. Using the conversion factor, your lux meter is a near-perfect PAR meter.

You can also find threads on other sites where people have converted one of these handheld lux meters to a PAR meter.

I believe you'd find these articles eye opening.



First, either of those numbers are great:

25,000 lux ÷ 50 = 500 PAR
45,000 lux ÷ 50 = 900 PAR​

Second, I wouldn't make any drastic changes if you already have corals growing.

Third, check out the info and links I put in my last post. One link is to a search that has actual results people have posted here. You can run the same search for PAR numbers and just convert them to lux by multiplying by 50 (the conversion factor for sunlight).

Just to quickly reiterate in a nutshell, anything from 20,000 lux up to 80,000 lux is likely to be acceptable. Probably lower on the range is better than higher.

OK so if I am reading 25,000 LUX (500 PAR) above water what would be my readings at 6" vertical intervals? I have a 50 gallon cube (24x24x20).
I am running a single AI Prime LED and the manufacture has 2 different publications where one says its max PAR is 500 and another says its max is 260.
FWIW I have my SPS 6-10" below the water line. It's a fairly new setup so I am not expecting tremendous growth yet but I am seeing some encrusting on a Tenius colony and growth on my Setosa and Birdsnest. All SPS are showing decent polyp extension.

 

[ncfishguy]

Following

 

[mcarroll]

they seem to be of the camp, 400 par on any given coral and above is a waste.

i think their data may need to be relooked upon...

https://www.researchgate.net/public...ral_Stylophora_pistillata_as_measured_in_situ

I may have missed something cuz I don't know whose data is being referred to, but Salty and that (once again excellent) reference appear to be in agreement.

I'm also still reading....am I missing something in the conversation though?

OK so if I am reading 25,000 LUX (500 PAR) above water what would be my readings at 6" vertical intervals?

I've wondered the same thing, my answer to myself has always been something like "Same as 6" below where it's 25,000 lux in the ocean! What kind of question is that??" and I'd be perfectly content using the light. No, seriously.

But what's been lacking in terms of a better answer was sorta presented nicely by way of this chart in the article Russ linked:

According to the Researchgate link, that's a chart of two meters' depth.

Excellent to have a concrete example. This is really the first good example of real measurements like this that I've seen. (Sweet!)

This chart also brings to mind how variable these measurements are from locale to locale, from day to day, etc. Water and sky conditions both have a huge influence on the character of the light that ultimately reaches (e.g.) two meters depth.

I can tell that corals in this area of the Red Sea, at this depth, are likely to experience peak PAR levels between 1100 and 900. (55,000 lux to 45,000 lux)

Those numbers look familiar (many or most commercial fixtures seem to top out around this level of intensity)...we know a lot of people that have a light field in their tank that's at least vaguely like the one these scientists studied.

(This is not a summary of the article at all, btw...just a mental wandering it provoked ...go read it if you haven't yet! )

 

[Russ265]

I may have missed something cuz I don't know whose data is being referred to, but Salty and that (once again excellent) reference appear to be in agreement.

I'm also still reading....am I missing something in the conversation though?



I've wondered the same thing, my answer to myself has always been something like "Same as 6" below where it's 25,000 lux in the ocean! What kind of question is that??" and I'd be perfectly content using the light. No, seriously.

But what's been lacking in terms of a better answer was sorta presented nicely by way of this chart in the article Russ linked:

According to the Researchgate link, that's a chart of two meters' depth.

Excellent to have a concrete example. This is really the first good example of real measurements like this that I've seen. (Sweet!)

This chart also brings to mind how variable these measurements are from locale to locale, from day to day, etc. Water and sky conditions both have a huge influence on the character of the light that ultimately reaches (e.g.) two meters depth.

I can tell that corals in this area of the Red Sea, at this depth, are likely to experience peak PAR levels between 1100 and 900. (55,000 lux to 45,000 lux)

Those numbers look familiar (many or most commercial fixtures seem to top out around this level of intensity)...we know a lot of people that have a light field in their tank that's at least vaguely like the one these scientists studied.

(This is not a summary of the article at all, btw...just a mental wandering it provoked ...go read it if you haven't yet! )

the "above 400 par is a waste" comment was refuted with the graph you brought up.

i do find this conversion fascinating though. a ballpark division by 50 would be very close to my par readings according to the meter and what you deduce.

just need more lux and par readings

 

[LakeCityReefs]

Russ do you have a LUX meter that reads pretty accurate so that you can compare a PAR reading too?
If so can you tell me what the drop in PAR is at 6 and 12" below water?

I'm about to put my phone in a zip lock bag to read the LUX in my tank.

 

[ksc]

I just checked my tank with my new Apogee mq500. At the surface, dead center, I'm getting about 1100. 6-7" inches down I'm getting about 500. I'm running 250w Radium MH. In the center of each side (4', 90gal) I get 250 on the sand. Move the sensor 8" to the side and it drops to 150.
Try to borrow/rent a par meter and map out your tank.

A lux meter is almost worthless for figuring par throughout your tank. For instance I get about 200 at the surface on the sides of my tank. At 6" deep it increases to 400.

 

[Russ265]

Russ do you have a LUX meter that reads pretty accurate so that you can compare a PAR reading too?
If so can you tell me what the drop in PAR is at 6 and 12" below water?

I'm about to put my phone in a zip lock bag to read the LUX in my tank.

yeah. sorry.
nothing but a phone lux meter. i already did my PAR metering. 300 on the sandbed 32' down.
sps in the middle of the tank get 500-550 par

 

[mcarroll]

I'm about to put my phone in a zip lock bag to read the LUX in my tank.

I wouldn't do that. ...unless your free phone upgrade is due! But if you do, post results!!

If you really want to measure under water, Milwaukee sells (or has sold) a lux meter with a submersible probe for $75. Seems like a reasonable cost.

I'm curious why you need to know the values at 6 and 12 inches but the surface measurements and other depths in the tank are less significant?

While you wait on some live PAR readings, maybe these will answer your data needs...

From reef2reef...per the comments in the thread, this has 500 PAR at the top:

http://s842.photobucket.com/user/gablett_photo/PAR/story
About 500 PAR at the top...this looks like a 24" deep tank with measurements every 6"...

Accounting for differences in power and lenses between tanks/fixtures, these maps are fairly predictable....I didn't have to search to find two that matched....I just had to find two that reported the measurement and the top of the water.

Naturally they matched.

This is a lot of why I'm happy with surface measurements.

Not to say we have to be in denial about what a difference water can make....just look at the difference illustrated here in this NOAA chart:


That's the same 100,000 lux (2000 PAR) at the water surface on each location – open water vs coastal – but look at the damping effect local conditions in coastal waters have!

Our tanks are much more homogenous with each other than that - well-filtered, et al. – so there would never be such a disparity in the effect of the the same light between two tanks unless something was drastically wrong. (Growing greenwater? Power supply burning out?)

 

[Russ265]

 

[LakeCityReefs]

I am getting the highest LUX readings from my white LED channel. The manufacture states PAR values that are not very intense however, I am very nervous to increase my whites past 60%.

Any thoughts on my current light settings?

 

[mcarroll]

Maybe others will have better ideas, but I just say dial in the colors to how you like them and then use the lux meter to set intensity.

The cool white and (~450nm) blues pretty much carry the load – the rest is for decoration or for minor effect. So you can set color however it makes sense to you. (I don't know how much power they have in the UV channel...probably not too significant, but regardless, be aware that UV is dangerous to eyeballs and humans in general.)

Most UV and Red light are filtered out almost completely in shallow water too, so that could be something keep in mind when setting the colors.


This might help with the UV component:
http://www.int-res.com/articles/meps/144/m144p109.pdf

Table 2 might be a good place to start deciphering. UV is not a universal component of reef lighting like we sometimes think...only in some locales.

 

[saltyfilmfolks]

I am getting the highest LUX readings from my white LED channel. The manufacture states PAR values that are not very intense however, I am very nervous to increase my whites past 60%.

Any thoughts on my current light settings?

what lux meter are you using. dont trust the phone app. its a phone. with an app. my reccomandation.

if you are getting coral browning because on high nutrients, you can increase the lights from 30,000 lux to 40,000 in two weeks. if you get bleaching you can now back off to 35000. no fake percentage games.
plus if you change lights and need to hang the new one higher you can test it. old light is 30k lux, replace the old one and set the new dimmer at 30klux again(or 20k lux to acclimate).
If you did that with a par meter, you would have to set all intensities and all color(w/b) balances to get the same par. White has higher par in led. if you have three colors or more to set how are you ever gonna guess how you get to 300 par. you can get to 300 par on just one chanell.
set the color to eye and measure the intensity, you can also measure and mark the individual colors percentage that got you there. I do. then you can back off the blues increase the white(or vice versa) and keep the same overall intensity on the tank..

you can now slowly increase the overall intensity safely or individual. set the color to eye so you can enjoy the tank. if you set the color for best growth like in nature your corals would be brown. like in nature. under full spectrum light 2 feet below the water.

how a par meter works, and a comparison of different models and that they are not really that efficient or accurate from brand to brand(hanna/api). and why I would only buy/rent apogee.
http://www.advancedaquarist.com/2013/2/equipment
also if you read and understand this article it will explain the very close relationship that lux and par have.(you cannot have a par reading without lux) also if you follow the article, if you have a lux and par meter you will figure out how to set your own lux par conversion number based on your light and individual settings. so you may want to only rent a par meter and buy a good lux meter.

A lux meter is almost worthless for figuring par throughout your tank.

mmmm, unless you know a lot about lux par and the adaptability of corals in thier uptake of light. its a very usefull tool esp to learn the relationship between the two and for newer reefers as its low cost. and if everyone had one you could post it along with you alk and ph for troubleshooting.

Move the sensor 8" to the side and it drops to 150.

because its closer to a dark object id bet. or is shadowed. you can also decrease your par by going bare bottom or painting a black background on your tank. or if using led with lenses your just outside of the hot spot of the lens.

at a certain point. its just chasing numbers, just like chasing ph etc. The much more challenging part is trying to figure out what coral likes what.

 

[LakeCityReefs]

what lux meter are you using. dont trust the phone app. its a phone. with an app. my reccomandation.

So im getting a full sun reading of about 150k LUX ÷ 50 = 3,000 PAR

There's a calibration where I could adjust it but I honestly don't know what the sun should be reading at my location.

If I read 30k LUX on my tank than I'm getting 600 PAR at the surface and should be able to grow SPS from the top to halfway hopefully.

At least this is a starting point for me.

 

[saltyfilmfolks]

thats a phone. and a camera. not a meter. dont trust it. 15 buck lux on amazon.

but the math is correct assuming best case light spectrum.(sun 50 or a MH)

and keep in mind its not sps its high light corals. like my pink paly's and my yellow leather. but not my tri color valeda. it seems to be a deeper water version of that sps and prefers lower bluer light.

so yea great starting point. and you know you have room to increase the intensity. with your est math now if you want to add intensity(and par) increase lux by 5000 lux and you have increased par by 100(remember it probably is really only 50 - 70 par with poorer quality lights (68? or a mars A @ 62 and or d riddles led older conversion numbers 67 and I d bet money a radion is closer to 57 or less even.).