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Lower Par SPS success


brad65ford

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brad65ford

Hey guys, we all see and hear so much about the demands of sps's with it comes to higher PAR lighting levels. For some reason most of my sps's enjoy lower par levels like 60-140 par. Now i'm not sure if this is become of the smaller tanks i have or because of which type of sps's i have. Regardless hopefully other here can stomp the myth that you need super bright lighting for sps success. Please post your success with lower light success!

 

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Nano sapiens

It's not so much a 'myth' as a reality at the time before reef aquariums were using as much violet/blue as we commonly use today.

 

PAR is a measurement of ALL wavelengths between 400-700nm. If the lighting is closer to a true 'Full Spectrum' you have to provide higher PAR in order for most Acros to thrive since PUR (photosynthetically usable radiation) would be relatively low if you did not. This is why you'll see comments like 'SPS need 400-700 PAR' in the older references when 6500K MHs and such were commonly used in order to provide enough intensity of the wavelengths used in photosynthesis.

 

Basically, if you are proportionally providing a lot more light in the Violet-Blue spectrum then you can produce higher PUR at relatively low PAR. I bet your light is quite 'blue', correct?

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brad65ford

Oh I do follow, yes they are pretty darn blue for sure. These led's are so confusing to me. My last lighting for my tank was 350w kessils and I could bearly turn the bluer (channel 1) up more then 20 percent with out upsettin the corals for some odd reason. These Orbit blues the corrals love which sure makes my head scratch. I have read that blue light par levels may not be as accure with a par meter regardles i'm seeing 140par on my green slimmer and its liking it.

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brad65ford

Very interesting if this is true, meaning you can run lower par as long as you have more lower blue nm light? The Orbit is said to have 445nm and 460cm along with 8000/12000kv Now i know its not full spectrum but does it need to be for good growth and coloration?

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Nano sapiens

The Kessils blue channel intensity was likely providing too much PUR which caused too much photosynthetically produced oxygen for the coral to deal with effectively. They will expel the Zooxanthellae ('bleaching') rather than be destroyed by the Zooxanthellae's oxygen byproduct (hydrogen peroxide, mostly). Factors are wavelenght(s), intensity and length of time/day the coral receives the blue light.

 

Correct, the common Apogee quantum sensor is less sensitive to light at the lower and higher ends of the visible light spectrum (400-700nm). For example, for measuring just violet light a correction factor of 30-40% is typical. With your quite blue light you could add an additional 20% or so and likely be 'in the ballpark' as to true PAR.

 

I needed ~200 PAR from my 'full spectrum' LEDs to induce a Red Planet Acro to start branching. If I had an old 6500K MH, I'd likely have needed ~350 PAR to produce the same result.

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Nano sapiens

Very interesting if this is true, meaning you can run lower par as long as you have more lower blue nm light? The Orbit is said to have 445nm and 460cm along with 8000/12000kv Now i know its not full spectrum but does it need to be for good growth and coloration?

 

One thing to remember is that the 445 and 460 are just the peaks, but other blue and some violet wavelenghs are are also produced. These lower wavelengths are used for photosynthesis and also cause florescence (the 'Pop' we see from Actinics). Providing a more full spectrum lighting stimulates some coral pigments and also renders non-florescent coloration properly to our eye. Example would be a red fish or coral with non-florescent pigment that would look near black under just blue light.

 

The 8000 and 12000K 'White' light are considered 'Cool White' and have a large blue spike, but less of the 'warmer' wavelengths you'd get with a neutral or warm white LED. You can now see why the light is producing a whole lot of 'Blue' wavelengths.

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13" but plan to have a partially dsb. Going to have a jawfish and so half of the tank will be around 4" of sand with it tapering down to around 1"towards the other.

 

So that gives a depth of 9-12"

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Nano sapiens

There is lab grade spectrometer equipment that can measure individual wavelengths and relative intensity accurately to determine PUR, but it's well beyond most hobbyist's means. I made a home-made spectrometer once, but since I don't have 'the real deal' to check it's accuracy against, I can't say if it is truly accurate.

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very neat for sure, still an amazing subject just like the whole hobby since there is no real answers to everything everyones doing since it would be text book and easy to duplicate. But seriously what doesn't make sense is how one led dio (lets say 420nm) giving off the same par is better or worse then the other makes? This whole debate of expensive LED systems and marketing has me scratching my head. Personally i've see some amazing tanks and growth with no name cheap fixtures also very low par compaired to what is "said" sps's are needed.

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Nano sapiens

We are lucky to have such a choice of LEDs now, but on the flip side it can also be confusing since we have such a choice of LEDs now :)

 

Standards are not as set as we see in MH and T5, so that's why you'll see a variety of LEDs (spectrum, voltage) as well as different approaches in the way the LED emitters are arrayed. Often DIYers have been at the forefront, with commercial fixtures lagging a bit behind. In a higher end fixture you'll typically see more features, more efficient power supplies and LEDs from respected manufacturers with better bins, more of the relatively expensive specialty LEDs that make up a 'full spectrum' system, etc. There's also the question of whether you want to buy from a respected brand with a good reputation and warranty, or buy cheap and take your chances with a 'no name' system.

 

Easiest way to make a decision is to find a top-notch tank similar to yours that uses an LED array and has lighting output you find pleasing...and grows/maintains corals over a long time period.

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