Par or ppf

[jfl14609]

Can anyone me the major difference I just grabbed a ppf meter from a friend and dont understand the difference from a par meter. Should the numbers be similar to those of a par meter. If possible answer this like your talking a 5 yeah old because Henry colf and I have been reading on it all day and don't get 99% of what we read

 

[superkat]

and i'm thinkin', you and henry aren't understanding it? that's bad. you guys are totally the brainy ones.

 

[jfl14609]

Only after a few beers and we havent started yet opps henry is on number 4

 

[superkat]

i heard the "pshhhhhhht" sound from here.

back to question:

Can anyone me the major difference I just grabbed a ppf meter from a friend and dont understand the difference from a par meter. Should the numbers be similar to those of a par meter. If possible answer this like your talking a 5 yeah old because Henry colf and I have been reading on it all day and don't get 99% of what we read

 

[dreaminmel]

Because I can't link to the forum... here is Sanjay's explanation from manhattanreefs.

"What is PPFD?
PPFD stands for Photosynthetic Photon Flux Density, and is the technically correct term when PAR (Photosynthetically Available Radiation) is measured as the number of photons of light falling on a given area in a given amount of time.. The units are micromoles per meter square per second. 1 micro mole is = 6.023X1017. So for example, when you see a value for PPFD=200 it means that there are 200X6.023X1017 photons falling on a 1 meter square area in one second.


What is difference between PAR and PPFD?
PAR is the Photsynthetically Available Radiation which is all radiation between 400-700 nm wavelength range. It can be measured in several units. Just like distance can be measured in feet, meters, etc. PAR can be measured in different units used to measure radiation. When PAR is measured by the number of photons falling on a given area in a given amount of time, this is called PPFD and the units used are micromoles per meter square per second."

 

[dreaminmel]

I'm going to see if I can link up a PPFD bulb/ballast rating chart here so you can see in relation what number ranges are used for quality rankings...

 

[superkat]

gotta love Mel.

 

[dreaminmel]

Lighting results for my ballast... PPFD uses much lower numbers.

 

[jfl14609]

I am thinking thats the article that gave henry and I a headache

 

[superkat]

oh no.............

 

[dreaminmel]

Grrr... gonna have to try a different doc type. In meantime I'm getting it from manhattanreefs dot com/lighting

Essentially PPFD uses much lower numbers than PAR. Best bulb on my magnetic M59 rates at 204ppfd and worst is at 94ppfd.

 

[Henry Colf]

Ok I got it thanks....

 

[jfl14609]

Grrr... gonna have to try a different doc type. In meantime I'm getting it from manhattanreefs dot com/lighting

Essentially PPFD uses much lower numbers than PAR. Best bulb on my magnetic M59 rates at 204ppfd and worst is at 94ppfd.

are those readings ppf cause I believe your runing 400 watters under luminarks I am running 250 watt with luminarks and my reading is 490 to 500 at the surface about 2 inches down

 

[dreaminmel]

No they're in ppfd, not ppf. Good god is there another measurement for light that's ppf? Hang on... let me post these two things together and see if anyone can decipher this mess...

"All quantum meters and sensors here measure Photosynthetic Photon Flux (PPF) as µmol m-2 s-1 for Photosynthetically Active Radiation (PAR) in the range of 350 to 650 nm." from arabidopsis.com

And then from above "PPFD stands for Photosynthetic Photon Flux Density, and is the technically correct term when PAR (Photosynthetically Available Radiation) is measured as the number of photons of light falling on a given area in a given amount of time.. The units are micromoles per meter square per second. 1 micro mole is = 6.023X1017. So for example, when you see a value for PPFD=200 it means that there are 200X6.023X1017 photons falling on a 1 meter square area in one second."

Anyone speak this language to know if they're the same? lmao I need a beverage...

 

[Henry Colf]

HaHaHa.... Mel I got the beverages workin..... takin off to the Great White North......

 

[jfl14609]

I dont speak it I have been waiting for sanjay to get online so I can talk to him and see if he can interpret for me

 

[bhovinga]

My understanding is that par is a measurement of photosynthetically usable light which is generally measured in ppfd.

So if you take a measurement of light in ppfd, par will be the usable portion of that light for photosynthesis. To get par from ppfd I think you need access to a graph of the spectrum of the light or a meter that does this automatically.

That is my understanding anyway.

 

[toddmh]

Because I can't link to the forum... here is Sanjay's explanation from manhattanreefs.

"What is PPFD?
PPFD stands for Photosynthetic Photon Flux Density, and is the technically correct term when PAR (Photosynthetically Available Radiation) is measured as the number of photons of light falling on a given area in a given amount of time.. The units are micromoles per meter square per second. 1 micro mole is = 6.023X1017. So for example, when you see a value for PPFD=200 it means that there are 200X6.023X1017 photons falling on a 1 meter square area in one second.


What is difference between PAR and PPFD?
PAR is the Photsynthetically Available Radiation which is all radiation between 400-700 nm wavelength range. It can be measured in several units. Just like distance can be measured in feet, meters, etc. PAR can be measured in different units used to measure radiation. When PAR is measured by the number of photons falling on a given area in a given amount of time, this is called PPFD and the units used are micromoles per meter square per second."

what the heck language is that in :hmm6:

 

[dreaminmel]

Not sure but between talk of photons and micro moles I'm picturing one heckuva Sci-fi movie. lol

 

[superkat]