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Discussion Starter · #1 ·
Im trying to understand lighting so I can figure out if I should upgrade my light. Im currently using a Nicrew LED Plus which is 95 PAR at 12" of Air. My Substrate is 18" on average so thats roughly 40Par. From what I understand this is considered medium light.

Im a visual learner and when I sit an look at my tank, it appears to be extremely bright to me. Im hoping someone can share pictures of a tank at low light PAR, med light PAR, and high light PAR so I can see the differences between them.

Just to confirm, when someone mentions that they are using more of the red and blue spectrum, they are referring more to kelvin adjustments, not PAR adjustments. PAR would be adjusted with a dimmer or physically changing the height of the light. Correct?
 

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Im trying to understand lighting so I can figure out if I should upgrade my light. Im currently using a Nicrew LED Plus which is 95 PAR at 12" of Air. My Substrate is 18" on average so thats roughly 40Par. From what I understand this is considered medium light.

Im a visual learner and when I sit an look at my tank, it appears to be extremely bright to me. Im hoping someone can share pictures of a tank at low light PAR, med light PAR, and high light PAR so I can see the differences between them.

Just to confirm, when someone mentions that they are using more of the red and blue spectrum, they are referring more to kelvin adjustments, not PAR adjustments. PAR would be adjusted with a dimmer or physically changing the height of the light. Correct?
Our eyes are a very poor judge of PAR. And pictures are worse.

Here is my tank under 200+ PAR. Means little in a picture. Only real way is to measure.

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40 PAR is medium low.

And yes blue and red refer only to color not PAR.
 

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Discussion Starter · #3 ·
You're correct. It looks dimmer than mine. is yours 200+ PAR at the substrate? So out of experience, is a higher PAR visually brighter?
 

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Discussion Starter · #5 ·
I understand. Im at the point of trying to figure out if I need to upgrade my light. Id like my reds to come in, so it seems as though I will need to upgrade it and then get my ferts figured out.
 

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Discussion Starter · #7 ·
If your at medium low like @Greggz suggest, then I think stems like Rotala R and AR will struggle. @Greggz do you know the minimum PAR those plants can "grow" not just exist under assuming all other conditions are met.
I agree. I'm also interested to learn that number. I'm already so invested, I'd feel like I was settling if I didn't try to achieve the reds. I appreciate a challenge but I need to understand also. And that's what I'm after, the understanding.
 

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If your at medium low like @Greggz suggest, then I think stems like Rotala R and AR will struggle. @Greggz do you know the minimum PAR those plants can "grow" not just exist under assuming all other conditions are met.
Good question.

In my experience, you really need somewhere in the area of 70+ PAR to bring most stems to really good health. At lower levels they will generally survive, but tend to get very leggy and weak as they struggle to get closer to the light.

And in that range of light, they will not show their best color. With the exception of a few species that are genetically red, the tank will be more monotone green. As PAR increases, so does separation of color. You get more orange, red, yellow, and even different shades of green.

But as you know, the higher the PAR the more you better know what you are doing and have things dialed in.
 

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Discussion Starter · #11 ·
I figured I'd share some close up pictures of my stems as of this evening. I'm seeing red shoots on the Rotala. I also cut down the AR. I got a couple pics of my Java fern as well as a very tiny new growth from my Echinodorus Aflame. 
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Cameras have an adjustment specifically designed to account for differences in how bright something is. ISO is typically set to auto on most cameras by default. The higher the ISO number the more sensitive the camera is to light. So any picture taken with auto iso will always appear about the same brightness level.

If you wanted to do your test you would at a minimum need to set iso to the same value on all cameras. BUT even then you have issues with different camera chips being more or less able to detect differences in brightness levels. Small chips will not be able to get the same kind of fidelity when light gets really bright. BUT even if every camera was the same make and model with the same settings for iso, white balance, shutter speed, and f-stop you still would not be able to get a good visual representation in pictures because pretty soon you would have the white areas of a picture (the highlights) getting blown out to just solid white and not actually get any detail in those areas. As the light got brighter you would have more and more highlights until the whole tank was just a big white square.

As Jeffkrol pointed out in the video he linked, par is not always a great way to measure light levels anyway, but it's the most wildly accepted way.

Anyway you can get rough estimates of different light brightness values by taking a lux meter or smart phone with the lux meter app, take a reading, and divide that reading by 80. This is a rough estimate but it should give you a way of figuring out the rough par of various light sources in your home.
 
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