wieselspor
Member
I hear people talking about the different lighting available. Whats the difference between 10k 20k 5k... is one better thatn another
Lighting
- Thread starter wieselspor
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hurt
Active Member
The visible light spectrum is from roughly 400nm to 700nm. As it increases from 400nm to 700nm the following are the visible spectrum we see in the exact order: violet, blue, green, yellow, orange, red. When we talk about K, that is Kelvin rating. The temperature to which a black object burns in terms of Kelvin rating is the color we actually see. A 6500K bulb is more on the orange/yellow side we see. A 10K bulb is more on the yellow/white side. A 14K is white/blue. 20K is more on the blue spectrum.
Generally speaking bulbs with a lower K value-i.e. 6500K put more PAR(photosynthetically active radiation) into the water. PAR is what makes corals grow. The more PAR the faster they will grow. But generally speaking bulbs with a lower K value don't give corals as much color/fluorescence as a higher K bulb will. A higher K bulb-i.e. 20K will put less PAR into the water(slower growth of corals), but the corals will generally show more colors and fluorescence. So it's really a tradeoff between color and growth, depending on what you want. Also bulbs on the lower end of the K rating generally have a less dramatic spectrum shift over their life, and as such they last longer. I personally run 10K MH's with VHO super actinics.
Generally speaking bulbs with a lower K value-i.e. 6500K put more PAR(photosynthetically active radiation) into the water. PAR is what makes corals grow. The more PAR the faster they will grow. But generally speaking bulbs with a lower K value don't give corals as much color/fluorescence as a higher K bulb will. A higher K bulb-i.e. 20K will put less PAR into the water(slower growth of corals), but the corals will generally show more colors and fluorescence. So it's really a tradeoff between color and growth, depending on what you want. Also bulbs on the lower end of the K rating generally have a less dramatic spectrum shift over their life, and as such they last longer. I personally run 10K MH's with VHO super actinics.
wieselspor
Member
Thanks that clears things up. What do you mean by super antics (20K?)
hurt
Active Member
Super Actinic .03 are the spectrum of the bulb in terms of nm, not in terms of K rating. These bulbs peak around 420nm, the violet-bluish range. They really cover the range between 410-435 nm(nanometers) overall. This spectrum has the power to affect chemical change, and it is this spectrum that give animals their fluorescence. The blue-violet spectrum is also the last spectrum to be filtered out by water-thus it penetrates the deepest-that's why the ocean appears blue.
If I just ran my 2 250w 10K MH's, my tank would look more of a yellow/white color. Because I also run VHO super actinics it's appearence is more of a blue/white, and also my corals fluoresce more because of these bulbs.
I am assuming you know the difference between VHO, T5, PC, and MH. The first three all have bulbs that are marketed as true actinics in terms of nanometers. URI makes VHO super actinic .03 bulbs and those are the bulbs I am referring to. In terms of K, I would say true actinics are at least a 20K bulb and higher. But I do not know the exact wavelength in terms of K rating.
If I just ran my 2 250w 10K MH's, my tank would look more of a yellow/white color. Because I also run VHO super actinics it's appearence is more of a blue/white, and also my corals fluoresce more because of these bulbs.
I am assuming you know the difference between VHO, T5, PC, and MH. The first three all have bulbs that are marketed as true actinics in terms of nanometers. URI makes VHO super actinic .03 bulbs and those are the bulbs I am referring to. In terms of K, I would say true actinics are at least a 20K bulb and higher. But I do not know the exact wavelength in terms of K rating.
twindadx2
New Member
:help: I have a 75 gal tank that i am trying as saltwater i have 50lbs of live sand approx. 80lbs of marshall island rock which i just found out last week that the (polyps) were not polyps but anenome majanos which i took care of with joes juice , still have a few but i think i am winning. also a protein skimmer seaclone 100 2 powerheads heater H.O.T magnum with charcole and a fluval 403 . I have 4 48" t-12 lighting for a total of 160 watts i know this is low for most ? but i have seen many "corals" that say low lighting or medium so the ? is how low is low or what will survive in my tank i dont want to purposely kill and surley dont want to throw the money away either... any and all help would be appreciated as i am a newbie thanks
kent'sreef
New Member
Simply put:
10000 = white looking tank (MH)
20000 = blue looking tank
I use the 20000 just beacause it fulfills the spectrum needed by all animals.
10000 = white looking tank (MH)
20000 = blue looking tank
I use the 20000 just beacause it fulfills the spectrum needed by all animals.
wieselspor
Member
Thanks everyone, ya learn something everyday.
hurt
Active Member
Kent's reef, all bulbs whether it's a 6500K, 10000K, or 20000K fulfill the spectrum needs of all corals. However each bulb peaks at different wavelengths. Furthmore each coral responds differently to different wavelengths, and as such some do better under different wavelengths of visable light than others do. A 6500K bulb will last as long as 2 years with little spectrum change(15%), while most 20K bulbs usually last only 3 months before there spectrum drastically shifts. Most 20K bulbs are dwarfed in PAR ratings compared to a 6500K bulb. But certain spectrums promote greater color pigmentation in different corals.
Upon BangGuys advice, google Dana Riddle, he has done a lot of research on this subject
Upon BangGuys advice, google Dana Riddle, he has done a lot of research on this subject
kent'sreef
New Member
Preference is probably the determining factor when purchasing a MH bulb. A 6500K may cover the spectrum needed to support any coral but if you have a stoney and its on the sand in a medium to deep aquarium, the light spectrum never reaches the animal. Most reputable books and websites suggest light supplementation is needed with any MH less than 10000K. I just wanted to clear things up, especially for some of the new guys.
hurt
Active Member
A 6500K may cover the spectrum needed to support any coral but if you have a stoney and its on the sand in a medium to deep aquarium, the light spectrum never reaches the animal.
It's actually the exact opposite. A 6500K will put MORE par on the bottom of a tank than a 20K will. Google Dana Riddle, he has done a lot of research on the subject. I'd post the link, but it contains ad's.
To give you an idea, one of the LFS here in Louisville used to run 10K MH's on their sps tank. This tank is not even more than 15' deep. Then he switched to 20K MH's. Then when I just went back in he switched back to 10K. I pretty much new the answer why he did, but I asked him to make sure. He said when he ran the 20K's the sps polyps were not extending much and growth was very minimal. He did say his clams were showing more color and thus he was selling a lot them. However he was not selling many sps at all. So he switched back to the 10K's and he said now they are growing much better and the polyp extension is also much greater=sales to him.
It's actually the exact opposite. A 6500K will put MORE par on the bottom of a tank than a 20K will. Google Dana Riddle, he has done a lot of research on the subject. I'd post the link, but it contains ad's.
To give you an idea, one of the LFS here in Louisville used to run 10K MH's on their sps tank. This tank is not even more than 15' deep. Then he switched to 20K MH's. Then when I just went back in he switched back to 10K. I pretty much new the answer why he did, but I asked him to make sure. He said when he ran the 20K's the sps polyps were not extending much and growth was very minimal. He did say his clams were showing more color and thus he was selling a lot them. However he was not selling many sps at all. So he switched back to the 10K's and he said now they are growing much better and the polyp extension is also much greater=sales to him.
kent'sreef
New Member
Well while trying to clear things up, maybe I did just the opposite, thanks for the correction. Trying to keep things simple, my intent was to convey that blue light waves (20000K)are considered more beneficial to marine amimals that live in deeper environments and receive very little red light which is filterd out by the water. As long as the bulb has a CRI over 90 it approximates the sun fairly well. Tanks usually have animals that originate in various conditions and would benefit from multiple MHs.
It is known that the 65's stimulates coral growth better than the 20000Ks. Also some hobbyist have reported better coraline growth under the 20000K's when employing multiple lamps in their tanks and coralline grows better under lower PAR levels. Watts are the best way to reach the bottom when considering a deeper aquarium.
It is known that the 65's stimulates coral growth better than the 20000Ks. Also some hobbyist have reported better coraline growth under the 20000K's when employing multiple lamps in their tanks and coralline grows better under lower PAR levels. Watts are the best way to reach the bottom when considering a deeper aquarium.