Hi all. One of the biggest and hardest thing for me getting into the hobby was understanding light. When I asked at many LFS how much light I needed for what, i got the eye roll and was told it was really too complicated. I tried some forums and was told the same, or flamed, or I needed a per meter. I found that pretty odd as well they dont know me or my capacity for learning, or That I have been measuring light for 20 years and manipulating filtering and using the visible spectrum for the same amount of time.
This led me to a major scientific break though.
These people dont know what the %&*%#&!!! they are talking about.
Here is how it works.
Light is measured in many ways, the most important is intensity, it is meaured in Footcandles and lux and umol pers2. The umol is a complex mathematical pain for most. so ill ignore it now.
In Lux and FC, light falls on an object and we want to know how much.
With a meter in the dark it is Zero.
During the brightest day, on average its about 100,000 lux.
Yes it changes with clouds seasons etc but scientists need a standard. Like celcius.
SO....What about PAR. Photosynthetically Useful Radiation
To maintain a standard they assigned a number to the best possible amount of par easily available to us. The sun.
The par of the sun on the same bright day is 2000 par.
Remember the same bright day is 100,000 lux......Right?
So that means there is a mathematical conversion factor from lux to par!
That mathematical conversion factor is called a Constant.
http://www.apogeeinstruments.com/conversion-ppf-to-lux/
http://www.advancedaquarist.com/2008/2/review
Each light source has a different amount of Photosynthetically Active Radiation.
So to break it down. If you put a par meter next to a Lux meter there will be a mathematical equivalent.
100,000 lux is 2000 par if the light source is the sun (divide lux by 50)
100,000 lux is 1200 par if the light is a fluorescent tube in your garage (divide by 80)
so each light contains a value of spectrum, a constant
A chinese Black box a mars aqua at full 1 to 1 white blue has a value of 63(took a long time to figure this out btw)
An ati t5 array with a 50 50 of coral plus and Blue plus is in the 45 to 50 range.
From D riddle and many Friendly folks I met with par meters.
Now I like my high light tank to be 40,000 lux at the top of the water. So if i used the....
Sun 800 par
Shop light 500 par
Mars BB 634 par
t5 888 par
Big difference there.
No the coral doesnt grow so good under a shop light and you need a whole lot of them too, but mainly it is the lack of the correct spectrum for the animals that we keep need.
And that is Pur.Photosynthetically Useful Radiation. and that does change from animal to animal. And there is a really really expensive meter for that too.
Many orchid growers DO use shop lights to grow their flowers. I do. Well the Mrs and her club.
Now on spectrum.
In this hobby many prefer more blue less blue etc, and the tool is there to help you track your changes. thats it. its not a rule book. If you notice the zoas like dirty water, in the next tank you match the Po no. so now match the light. In intensity. and color.
IMO set the color to your eye.(or how it is right now)
Measure the white chanel only in lux. Measure the blue channel only in lux. measure them combined.
A quick interesting note, at the same intensity, a Mars radion or whatever, with more blue in the mix ratio has less par, this is because it is only a very narrow band of the spectrum.
So a white(not truly white btw) reef 14k light has more par than an actinic.
But as we know many of our animals like it so what that means the light has more Photosynthetically Useful Radiation to those animals.
So high par numbers dont really mean much in fact, and the main use of the meter is to be able accurately get into the ball park and and accurately make changes depending on the reaction of the animal we are lighting.
If you took the time to read Dana's article and the One from apogee, youll notice my numbers are a bit off. Sun 54, thats for easy math. Imo its really all you need and most will ever need to know. its an estimate.
But it's Just like manipulating Nutrients. In fact actually like manipulating nutrients. Light is food.
Light is a parameter and needs to be checked accurately , and lux is a very good tool for the average reefer.
And as we just learned now about par and pur, a par meter aint all its cracked up to be either, is it. In a reef tank I could blast the red and yellow and get a lot higher par on the meter. And interestingly the best way ti lower your apr is use a black background. A quick way to bring it up. a blue or white one. Thats because its bouncing color or intensity or in the case of black absorbing both.
Thats yet another reason I use lux. Its the actual amount of light falling on a surface.its not reflected, its not influenced by color.
If I know its good a good spectrum light source all I need to know now is how much of it there is.
On acclimation, and upgrade.
Test the lux. then drop it 30%,now you have an actual number to do with and not a dial.
This will help prevent burning your corals.
If the new light has a much higher available par, like from ATI Coral plus(38 constant) you wont shock your coral because you reduce the over all intensity of the light.
On dimmables you can now increase intensity by 1500 lux 2500 lux or 5000 lux increments.
You can IMO pretty safely Estimate, 5k lux as 100par
This is the lux meter I use on the tank 13.99
https://www.amazon.com/dp/B00AQT68CO...1&keywords=lux
a demo of how to use it
http://www.reef2reef.com/threads/lig...mfolks.248417/
It doesn't answer a lot of questions like what is the best light for what coral, does this coral like more or less of what. Thats our job.
Edits:
For the newer reefers hes a couple of good links to strart understanding spectrum and par, and a bit more on intensity.
A pretty good one, a bit dated perhaps, but overall an nice introduction to lighting.
http://www.reeftank123.com/lighting/lighting.html
Another a little bit more in depth with one of my personal Guru's Dana Riddle....
http://www.advancedaquarist.com/2013/12/lighting
Deep right? After your head stops hurting check this out.
When Im bored and I've watched all the cat videos in the internet I look at stuff like this. Par charts and maps.
Notice from species to species and tank to tank theres similarities in what and how the tanks are stocked,and placed, according to the amount and light and par.
https://www.google.com/search?tbm=is...gQ9C8ICQ&dpr=1
So for the uninitiated, what this means is, you really should know how much light you have and choose your livestock accordingly. If you leave the lfs with a Pearlberry acro and a leptoseris and expect to have great results in your 30 g biocube you may run into trouble. Unless you know where to put them.
This is really one of the things on my mind personally(im a noob) and as learn more and more about corals they like different stuff, color and intensity.
Ive had zoas right next to each other that one dies one grows great. I put the dead ones in more light,(a LOT more in one case) and not only did it bloom it went nuts.
But both ARE zoas right? it's why they say to move them around until you find the sweet spot. Some are just from lower light. And thats the challenge. All coral come from all depths even within the same families.
So when you go to a brother(or sister) reefers house to get some frags, look and ask where they are in the tank, for flow and for light.
Heck. Take your lux meter with you.
I promise Ill re read this again sober and get it edited.
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Originally Posted by unbereefable
