PAR what???

sefrayser · 09/17/2011, 09:05 AM

I keep reading about PAR and how it is important. What is PAR exactly? How much is to much PAR? How come LED and MH PAR is so much different? Companies compare their LED to MH and from what I read the PAR number between the MH and LED are very different. Is it that LED penetrate more where MH dissipates thru the water quickly? I have a MH and I am thinking of getting the SOL. Just want to understand PAR and how the LED light spectrum or wavelengths are different from MH.

t4zalews · 09/17/2011, 09:29 AM

PAR = photosynthetic active radiation, how do I want to word this...its a measure of how much usable light there is at a certain point. I'm probably not explaining this correctly so someone can help me out. I just bought a PAR meter myself to see what my tank was reading cuz I was considering going to a 400w from my 2x250w. I deal mainly with clams and SPS, they handle PAR levels of 200-1000+. The bottom of my tank runs 200 and the highest point about 815.

You can have too much PAR depending on what you're keeping. Too much PAR can lead to bleaching. I think any coral can accept a certain amount of PAR given it is properly acclimated to the light.

About LED's, I can't say much on the subject as I've never dealt with them. Still reading and learning myself.

sefrayser · 09/17/2011, 10:41 AM

Thats a lot more than what I knew....thanks. I want to get LED but I am not 100% sold on them.

v3ngence · 09/17/2011, 10:46 AM

Fluorescents put out a wider color spectrum than LEDs but have to be changed every six months/year. LEDs are more efficient and run cooler but cost more to setup.

I think LEDs are a viable choice for all but the most light-selective organisms, but I have heard stories of corals loosing color due to the narrow spectrum.

09/17/2011, 09:05 AM	#1
sefrayser Registered Member Join Date: Sep 2010 Posts: 498	PAR what??? I keep reading about PAR and how it is important. What is PAR exactly? How much is to much PAR? How come LED and MH PAR is so much different? Companies compare their LED to MH and from what I read the PAR number between the MH and LED are very different. Is it that LED penetrate more where MH dissipates thru the water quickly? I have a MH and I am thinking of getting the SOL. Just want to understand PAR and how the LED light spectrum or wavelengths are different from MH.

09/17/2011, 09:29 AM	#2
t4zalews 65g Ritteri Tank Join Date: Mar 2009 Location: Royal Oak, MI Posts: 2,673	PAR = photosynthetic active radiation, how do I want to word this...its a measure of how much usable light there is at a certain point. I'm probably not explaining this correctly so someone can help me out. I just bought a PAR meter myself to see what my tank was reading cuz I was considering going to a 400w from my 2x250w. I deal mainly with clams and SPS, they handle PAR levels of 200-1000+. The bottom of my tank runs 200 and the highest point about 815. You can have too much PAR depending on what you're keeping. Too much PAR can lead to bleaching. I think any coral can accept a certain amount of PAR given it is properly acclimated to the light. About LED's, I can't say much on the subject as I've never dealt with them. Still reading and learning myself. __________________ - Taylor - 65g - Radion XR30 G3 Pro x2 - Deltec SCA 1351 - APEX - Tunze - Vortech

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09/17/2011, 10:41 AM	#3
sefrayser Registered Member Join Date: Sep 2010 Posts: 498	Thats a lot more than what I knew....thanks. I want to get LED but I am not 100% sold on them.

09/17/2011, 10:46 AM	#4
v3ngence Registered Member Join Date: Sep 2011 Posts: 34	Fluorescents put out a wider color spectrum than LEDs but have to be changed every six months/year. LEDs are more efficient and run cooler but cost more to setup. I think LEDs are a viable choice for all but the most light-selective organisms, but I have heard stories of corals loosing color due to the narrow spectrum.