What is PAR and how much do we need?

The Photosynthetic Active Radiation (PAR) is a term used within the reef tank community when talking about lighting. Lighting is one of the most importing aspects of the reef aquarium, partly because many aquarium organisms require lighting to maintain or increase their growth and too high of a PAR can increase the growth of unwanted algae. Photosynthetic is the process by which these organisms transform light energy into food. Corals have tiny plants called zooxanthellae living within their tissue and so together they are called photosynthetic. The PAR is the measurement of light emission within the photosynthetic range of 400-700nm (nm is Nano-meter).

Screen Shot 2021-01-12 at 1.05.23 PM.png

There are a few ways we can measure the lighting in the aquarium, such as lumens and lux meters but we are talking about PAR. Most, if not all, PAR meters are actually favorited within the reef community because they work well with LED lighting. I purchased an Apogee MQ-510 but I think any LED meter will be fine.


Screen Shot 2021-01-12 at 1.06.06 PM.png

When I purchased this meter, there was no instruction on how to use the meter but the instructions can be viewed from Apogee’s website. You can search the internet, especially YouTube, and find different ways of testing…It is really easy. One item to note while using the meter, the PAR displayed will have a fluctuation range of reading.

For me, just starting out adding corals in my saltwater aquariums, my knowledge was not up to the challenge. My main problem was when purchasing corals from either an online store or local store, the descriptions stated the required lighting needs such as low, moderate, high, or extreme light. But what do these levels mean? Without a discussion on more specifics information regarding PAR, I want to talk about these few requirement levels.

In general, corals with low values are considered to less than 100 and high values are generally over 250/300, so that means anything in the middle is medium values.
  • Soft corals are low values
  • LPS corals are medium values
  • SPS corals are high values
From my research, the below table has a little more detail:

SpeciesLight LevelPAR Range
Low light LPSLow50 - 100
Soft CoralsLow – Moderate50 - 200
LPSModerate100 - 200
Derasa Clams, Anemones SPSHigh200 - 300
Montipora and other SPSIntense300 - 400
Crocea, Maxima Clams, AcroExtreme400 – 500+

Recap:
  • Low < 100
  • Moderate 100 – 200
  • High 200 – 300
  • Intense 300 – 400
  • Extreme > 400
With this rule of thumb, most corals will adapt to different levels when given time to acclimate. Such as LPS corals can handle greater PARs up to 500, and soft corals will adjust to PAR over 200 with adequate time to adjust so they can adapt to a wide range of lighting over time.

The lighting schedule can also play a huge role in the success of the reef aquarium regarding PAR levels. I tried to match the Sun with the respect to the rotation around the Earth. I set up my LED lighting on Apex Fusion to mirror Sun’s rise and fall. Here is what my schedule looks like.

Screen Shot 2021-01-12 at 1.07.55 PM.png


The schedule has changed a few times since the beginning and I am sure it will change again.

Chasing PAR values can be time-consuming but can be more beneficial and observe these values based on individual needs and reactions. When purchasing a new coral and knowing the PAR before adding a coral into the new population can be a huge advantage. Something else to consider if no PAR meter is available, in the lower lights levels corals will lose their color and grow slower but if too bright, the corals will bleach and die faster.
 
Last edited:

Dana Riddle

2500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Sep 10, 2011
Messages
3,162
Reaction score
7,520
Review score
+0 /0 /-0
Location
Dallas, Georgia
I see messages implying PAR values exceeding known Saturation Points are OK. In many cases they are not - a coral can be bleached and it is impossible to visually judge this. A non-intrusive chlorophyll meter is needed unless one wants to sacrifice a portion of the coral and extract photopigments for analyses. As far as I know, I am the only hobbyists owning one of the $3,000 meters. If you have one (Opti-Sciences) please drop me a line. Generation of reflective proteins might add some protection against excessive light. Perhaps some of the fluorescent proteins do as well. In the case of branching corals, the exposed areas can be bleached while the shaded portions have a healthy zoox population.
 

Freenow54

Valuable Member
Review score
+0 /0 /-0
View Badges
Joined
Mar 5, 2021
Messages
1,088
Reaction score
925
Review score
+0 /0 /-0
Location
Canada
The Photosynthetic Active Radiation (PAR) is a term used within the reef tank community when talking about lighting. Lighting is one of the most importing aspects of the reef aquarium, partly because many aquarium organisms require lighting to maintain or increase their growth and too high of a PAR can increase the growth of unwanted algae. Photosynthetic is the process by which these organisms transform light energy into food. Corals have tiny plants called zooxanthellae living within their tissue and so together they are called photosynthetic. The PAR is the measurement of light emission within the photosynthetic range of 400-700nm (nm is Nano-meter).

Screen Shot 2021-01-12 at 1.05.23 PM.png

There are a few ways we can measure the lighting in the aquarium, such as lumens and lux meters but we are talking about PAR. Most, if not all, PAR meters are actually favorited within the reef community because they work well with LED lighting. I purchased an Apogee MQ-510 but I think any LED meter will be fine.


Screen Shot 2021-01-12 at 1.06.06 PM.png

When I purchased this meter, there was no instruction on how to use the meter but the instructions can be viewed from Apogee’s website. You can search the internet, especially YouTube, and find different ways of testing…It is really easy. One item to note while using the meter, the PAR displayed will have a fluctuation range of reading.

For me, just starting out adding corals in my saltwater aquariums, my knowledge was not up to the challenge. My main problem was when purchasing corals from either an online store or local store, the descriptions stated the required lighting needs such as low, moderate, high, or extreme light. But what do these levels mean? Without a discussion on more specifics information regarding PAR, I want to talk about these few requirement levels.

In general, corals with low values are considered to less than 100 and high values are generally over 250/300, so that means anything in the middle is medium values.
  • Soft corals are low values
  • LPS corals are medium values
  • SPS corals are high values
From my research, the below table has a little more detail:

SpeciesLight LevelPAR Range
Low light LPSLow50 - 100
Soft CoralsLow – Moderate50 - 200
LPSModerate100 - 200
Derasa Clams, Anemones SPSHigh200 - 300
Montipora and other SPSIntense300 - 400
Crocea, Maxima Clams, AcroExtreme400 – 500+

Recap:
  • Low < 100
  • Moderate 100 – 200
  • High 200 – 300
  • Intense 300 – 400
  • Extreme > 400
With this rule of thumb, most corals will adapt to different levels when given time to acclimate. Such as LPS corals can handle greater PARs up to 500, and soft corals will adjust to PAR over 200 with adequate time to adjust so they can adapt to a wide range of lighting over time.

The lighting schedule can also play a huge role in the success of the reef aquarium regarding PAR levels. I tried to match the Sun with the respect to the rotation around the Earth. I set up my LED lighting on Apex Fusion to mirror Sun’s rise and fall. Here is what my schedule looks like.

Screen Shot 2021-01-12 at 1.07.55 PM.png


The schedule has changed a few times since the beginning and I am sure it will change again.

Chasing PAR values can be time-consuming but can be more beneficial and observe these values based on individual needs and reactions. When purchasing a new coral and knowing the PAR before adding a coral into the new population can be a huge advantage. Something else to consider if no PAR meter is available, in the lower lights levels corals will lose their color and grow slower but if too bright, the corals will bleach and die faster.
I really could use some direction as to a publication regarding corals. My knowledge is very limited. I try to follow links but the acronyms, and names mean nothing to me at this point
 

Freenow54

Valuable Member
Review score
+0 /0 /-0
View Badges
Joined
Mar 5, 2021
Messages
1,088
Reaction score
925
Review score
+0 /0 /-0
Location
Canada
The Photosynthetic Active Radiation (PAR) is a term used within the reef tank community when talking about lighting. Lighting is one of the most importing aspects of the reef aquarium, partly because many aquarium organisms require lighting to maintain or increase their growth and too high of a PAR can increase the growth of unwanted algae. Photosynthetic is the process by which these organisms transform light energy into food. Corals have tiny plants called zooxanthellae living within their tissue and so together they are called photosynthetic. The PAR is the measurement of light emission within the photosynthetic range of 400-700nm (nm is Nano-meter).

Screen Shot 2021-01-12 at 1.05.23 PM.png

There are a few ways we can measure the lighting in the aquarium, such as lumens and lux meters but we are talking about PAR. Most, if not all, PAR meters are actually favorited within the reef community because they work well with LED lighting. I purchased an Apogee MQ-510 but I think any LED meter will be fine.


Screen Shot 2021-01-12 at 1.06.06 PM.png

When I purchased this meter, there was no instruction on how to use the meter but the instructions can be viewed from Apogee’s website. You can search the internet, especially YouTube, and find different ways of testing…It is really easy. One item to note while using the meter, the PAR displayed will have a fluctuation range of reading.

For me, just starting out adding corals in my saltwater aquariums, my knowledge was not up to the challenge. My main problem was when purchasing corals from either an online store or local store, the descriptions stated the required lighting needs such as low, moderate, high, or extreme light. But what do these levels mean? Without a discussion on more specifics information regarding PAR, I want to talk about these few requirement levels.

In general, corals with low values are considered to less than 100 and high values are generally over 250/300, so that means anything in the middle is medium values.
  • Soft corals are low values
  • LPS corals are medium values
  • SPS corals are high values
From my research, the below table has a little more detail:

SpeciesLight LevelPAR Range
Low light LPSLow50 - 100
Soft CoralsLow – Moderate50 - 200
LPSModerate100 - 200
Derasa Clams, Anemones SPSHigh200 - 300
Montipora and other SPSIntense300 - 400
Crocea, Maxima Clams, AcroExtreme400 – 500+

Recap:
  • Low < 100
  • Moderate 100 – 200
  • High 200 – 300
  • Intense 300 – 400
  • Extreme > 400
With this rule of thumb, most corals will adapt to different levels when given time to acclimate. Such as LPS corals can handle greater PARs up to 500, and soft corals will adjust to PAR over 200 with adequate time to adjust so they can adapt to a wide range of lighting over time.

The lighting schedule can also play a huge role in the success of the reef aquarium regarding PAR levels. I tried to match the Sun with the respect to the rotation around the Earth. I set up my LED lighting on Apex Fusion to mirror Sun’s rise and fall. Here is what my schedule looks like.

Screen Shot 2021-01-12 at 1.07.55 PM.png


The schedule has changed a few times since the beginning and I am sure it will change again.

Chasing PAR values can be time-consuming but can be more beneficial and observe these values based on individual needs and reactions. When purchasing a new coral and knowing the PAR before adding a coral into the new population can be a huge advantage. Something else to consider if no PAR meter is available, in the lower lights levels corals will lose their color and grow slower but if too bright, the corals will bleach and die faster.
Is there a publication that I can get to expand my knowledge on coral?
 

rgulrich

Active Member
Review score
+0 /0 /-0
View Badges
Joined
Nov 27, 2018
Messages
182
Reaction score
311
Review score
+0 /0 /-0
Location
Marriottsville, MD
Is there a publication that I can get to expand my knowledge on coral?
A sticky on this lighting forum started by Dana. Good read for start with lighting terminology. After that, ask away on specific areas of focus.
Cheers, Ray
 

MnFish1

10K Club member
Review score
+0 /0 /-0
View Badges
Joined
Dec 28, 2016
Messages
15,445
Reaction score
16,174
Review score
+0 /0 /-0
I see messages implying PAR values exceeding known Saturation Points are OK. In many cases they are not - a coral can be bleached and it is impossible to visually judge this. A non-intrusive chlorophyll meter is needed unless one wants to sacrifice a portion of the coral and extract photopigments for analyses. As far as I know, I am the only hobbyists owning one of the $3,000 meters. If you have one (Opti-Sciences) please drop me a line. Generation of reflective proteins might add some protection against excessive light. Perhaps some of the fluorescent proteins do as well. In the case of branching corals, the exposed areas can be bleached while the shaded portions have a healthy zoox population.
Interesting. So - it was always my impression that bleaching meant 'turn white'. Are you saying that the tops turn 'white' and the shaded areas remain 'colorful' - or are you saying that the top areas (under the higher par) a lighter colored than the bottom? Would you be able to post a picture/example? Thanks!
 

oreo5457

2500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Sep 18, 2017
Messages
3,655
Reaction score
2,171
Review score
+0 /0 /-0

oreo5457

2500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Sep 18, 2017
Messages
3,655
Reaction score
2,171
Review score
+0 /0 /-0
Interesting. So - it was always my impression that bleaching meant 'turn white'. Are you saying that the tops turn 'white' and the shaded areas remain 'colorful' - or are you saying that the top areas (under the higher par) a lighter colored than the bottom? Would you be able to post a picture/example? Thanks!
 

Freenow54

Valuable Member
Review score
+0 /0 /-0
View Badges
Joined
Mar 5, 2021
Messages
1,088
Reaction score
925
Review score
+0 /0 /-0
Location
Canada
Thank you for the reply. As I have stated in other posts. I take the Responsibility of Life in my tank very seriously. I have first hand experience of what can go wrong, after buying an :" established tank " per my son, and brining it out of the abyss. I do not have a chlorophyll meter. I was reading a thread, and assumed I could get close with a Lux meter, which I just bought, and now realize it was a big mistake. Now I am going to get an Apogee MQ510. What brought my attention to the deeper part of the subject is the PAR posting page you started, and saw the values. Which are much lower than I expected. My situation is I am staring a new tank, I have cycled it, and am now adding fish. Per BRS video I am leaving the lights off for now. They are a pair of Aquanest M8's. So has preset LPS, and SPS settings. I asked the question about what you do if you have different coral with no answer. I understand how basic my information is at this point. Regarding the tank and the light height amongst dozens of other factors. Could you expand on " generation of reflective proteins"? My Interest was raised by the post from ShepherdReefer
 

Chaos2034

Community Member
Review score
+0 /0 /-0
View Badges
Joined
May 17, 2020
Messages
81
Reaction score
87
Review score
+0 /0 /-0
Never measured PAR...probably never will :rolleyes:

How do I get my corals to grow so well? I let THEM tell me what they need, instead of assuming....I know what's best for them :cool:

I've literally put "low" light corals, up with my SPS and had them explod with growth. The best indicators of good lighting - is paying attention to your tank.

IMO - people spend FAR too much time concerned about lighting (and it's not their fault....company's push "good" lighting hard). Anyone's who's who's reefing....for more than a few months, as seen epic tanks - in even, the most of basic lighting (we talking like stock BioCube LEDs) :eek:

Lighting....Ive found, is the easiest part of reefing. 1/4 of a successful tank...is lighting - people get so wrapped up in lighting, the miss just feeding their corals properly and ensuring their levels are strong.
 

Freenow54

Valuable Member
Review score
+0 /0 /-0
View Badges
Joined
Mar 5, 2021
Messages
1,088
Reaction score
925
Review score
+0 /0 /-0
Location
Canada
Are you talking about a 'general' publication about corals, or a publication about 'coral lighting'?
Seems my post got lost. One that distinguishes the different family's for general knowledge would be a start. However I am after specific information as to that corals lighting requirements as well
 

Freenow54

Valuable Member
Review score
+0 /0 /-0
View Badges
Joined
Mar 5, 2021
Messages
1,088
Reaction score
925
Review score
+0 /0 /-0
Location
Canada
Never measured PAR...probably never will :rolleyes:

How do I get my corals to grow so well? I let THEM tell me what they need, instead of assuming....I know what's best for them :cool:

IMO - people spend FAR too much time concerned about lighting (and it's not their fault....company's push "good" lighting hard). Anyone's who's who's reefing....for more than a few months, as seen epic tanks - in even, the most of basic lighting (we talking like stock BioCube LEDs) :eek:

Lighting....Ive found, is the easiest part of reefing. 1/4 of a successful tank...is lighting - people get so wrapped up in lighting, the miss just feeding their corals properly and ensuring their levels are strong.
Well I am not in the position to argue. I have a starter tank that is 10 years old at least that I inherited. My son kept throwing money at it fish, and coral. We lost a lot of the coral. Why? Now I realize could have been a lot of things. Also I put a " razor " light on it guessed as to the levels. Some coral thrived and multiplied Why? I assumed since my parameters are spot on that it was lighting. I just want to have every step covered. I spent $ 500 on an RO system, and DI filter for instance. Made a huge improvement on the tank I am talking about
 

Chaos2034

Community Member
Review score
+0 /0 /-0
View Badges
Joined
May 17, 2020
Messages
81
Reaction score
87
Review score
+0 /0 /-0
Well I am not in the position to argue. I have a starter tank that is 10 years old at least that I inherited. My son kept throwing money at it fish, and coral. We lost a lot of the coral. Why? Now I realize could have been a lot of things. Also I put a " razor " light on it guessed as to the levels. Some coral thrived and multiplied Why? I assumed since my parameters are spot on that it was lighting. I just want to have every step covered. I spent $ 500 on an RO system, and DI filter for instance. Made a huge improvement on the tank I am talking about
Yep....thats what I mean.

I have seen some mind blowing tanks - with lighting that, well shouldnt grow grass! Lol

You have everything from stock LEDs on a $500 tank to high-end Radions - and yet, corals grow. How? How can person A.....be as successful with their $200 reef light as person B, with their $2000 reef light?

ONE reason - corals adapt. It's crazy, how we don't give these animals more credit. Corals are extremely good at adapting to the light they receive. As long as you are meeting the "basic" needs (when it comes to lightin) - corals 100% thrive. We see it....every, single day.

As I said though.....lighting is the easiest part of the equation.

Keeping GOOD water - balancing nutrients (not too high, not too low) - maintaining minerals and elements - ensuring what corals actually use to grow, are present.....is the real key.

Its mind blowing....you'll see reefers spend THOUNSANDS of dollars on their lights - and are using an API test kit or trying to maintain stability, by dosing manually or think - the best way to grow corals, is to change your lighting schedule every other week. ;Facepalm

Reefing....IMO, is as complicated as you wanna make it.
 

MnFish1

10K Club member
Review score
+0 /0 /-0
View Badges
Joined
Dec 28, 2016
Messages
15,445
Reaction score
16,174
Review score
+0 /0 /-0

MnFish1

10K Club member
Review score
+0 /0 /-0
View Badges
Joined
Dec 28, 2016
Messages
15,445
Reaction score
16,174
Review score
+0 /0 /-0
Seems my post got lost. One that distinguishes the different family's for general knowledge would be a start. However I am after specific information as to that corals lighting requirements as well
The problem here - is that is a really general question. I would suggest to you that you go to the forum for the coral you're interested in - and just start reading 'topics'. I.e. soft corals, LPS, SPS forums. You will quickly get an idea. There is no magic IMHO. Here are a couple general points that I hope help:

1. All coral like clean water with good parameters (in general)
2. soft corals require < light than LPS requiring < than SPS corals
3. IMHO - LPS thrive with some dirty water now and then - that they can filter (like when you clean the glass)
4. I (personally) am not a believer in coral foods, additives, etc. I let the coral eat the small pieces of food - some of which I grind into very small particles
5. Lighting - (this is what I wanted clarity from the expert @Dana Riddle) - too little light is bad (long-term) - my interpretation - is that on the reef - where it can sometimes be cloudy for a week or more at a time - little light hurts growth - but not coral itself. Too much light - too quickly can cause problems. A PAR meter (which you can borrow from an LFS - or rent - or buy) can tell you where your light is at.
6. It is also my impression that the higher the alkalinity and the lower the flow - the more light-sensitive corals become.

Hope this helps some
 

oreo5457

2500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Sep 18, 2017
Messages
3,655
Reaction score
2,171
Review score
+0 /0 /-0
Thanks - I was asking Dana what he meant - but appreciate the article
Normally I wouldn't have answered but Dana seems a bit awol atm so next best thing(?).
The link not me. :)

A fun read...
 
Last edited:

MnFish1

10K Club member
Review score
+0 /0 /-0
View Badges
Joined
Dec 28, 2016
Messages
15,445
Reaction score
16,174
Review score
+0 /0 /-0
Normally I wouldn't have answered but Dana seems a bit awol atm so next best thing(?).
The link not me. :)

A fun read...
thanks - appreciated - I wanted just a response from Dana on that one question - :).
 

Freenow54

Valuable Member
Review score
+0 /0 /-0
View Badges
Joined
Mar 5, 2021
Messages
1,088
Reaction score
925
Review score
+0 /0 /-0
Location
Canada
The problem here - is that is a really general question. I would suggest to you that you go to the forum for the coral you're interested in - and just start reading 'topics'. I.e. soft corals, LPS, SPS forums. You will quickly get an idea. There is no magic IMHO. Here are a couple general points that I hope help:

1. All coral like clean water with good parameters (in general)
2. soft corals require < light than LPS requiring < than SPS corals
3. IMHO - LPS thrive with some dirty water now and then - that they can filter (like when you clean the glass)
4. I (personally) am not a believer in coral foods, additives, etc. I let the coral eat the small pieces of food - some of which I grind into very small particles
5. Lighting - (this is what I wanted clarity from the expert @Dana Riddle) - too little light is bad (long-term) - my interpretation - is that on the reef - where it can sometimes be cloudy for a week or more at a time - little light hurts growth - but not coral itself. Too much light - too quickly can cause problems. A PAR meter (which you can borrow from an LFS - or rent - or buy) can tell you where your light is at.
6. It is also my impression that the higher the alkalinity and the lower the flow - the more light-sensitive corals become.

Hope this helps some
Since using RO water, and using filter media, and cloth for Nitrates it not only let me control the algae, but also my leathers which at one point I split are coming on beutifully
 

How much of your saltwater reef tank is automated?

  • Nothing is automated

    Votes: 29 11.7%
  • 25% or so

    Votes: 78 31.5%
  • 50% or so

    Votes: 56 22.6%
  • 75% or so

    Votes: 56 22.6%
  • Close to 100%

    Votes: 28 11.3%
  • Totally Automated (we need proof)

    Votes: 1 0.4%
Deltec
Top