How do you figure par?

[flitabout]

I have been wondering how you figure par. The closest I could find put mine stupid high but that was with my brand fixture but several inches longer than the one I have. Would I have to get a meter or is there another way to figure it and at least get a close number? Do I even need to?

 

[Brian_Nano12g]

What kind of light is it and inches?

 

[flitabout]

Odyssea T5 Aquarium Lighting My tank is a 37g tall and from the light to the substrate it is 20 inches.

 

[J.Mcpeak]

Use a PAR meter or there are methods using a dslr. There are calculators online.

 

[flitabout]

I have no idea dslr is and I will look up a calculator. I really can't afford a meter atm.

 

[Sillyfishies]

Pretty much impossible to get PAR without a meter. There's too many variables.

 

[J.Mcpeak]

Dslr is a camera, Digital single lens reflex. Nikon Canon Olympus Sigma Leica. Hope that helps a bit. You may be able to rent the PAR meter. You can rent lenses but I'm not sure about cameras.

 

[J.Mcpeak]

Pretty much impossible to get PAR without a meter. There's too many variables.

Agreed, I've read about various methods but they yield varying results. Some idea can be gained which involves metering white balance setting f stop and ISO then letting the camera pick the exposure time, this info of ISO F and E is entered into a calculator. Sounds complicated to me.

 

[Brian_Nano12g]

If you want an inexpensive PAR meter that seems to be reasonably accurate for good "estimates", there's a guy named Hoppy on TPT that sells DIY PAR meters.

http://www.plantedtank.net/forums/showthread.php?t=456490&highlight=

Otherwise, you can use charts that estimate PAR based on a few factors: 1. Number of bulbs, 2. Reflector quality, and 3. Distance.

Based on those factors, which I "think" Odyssea is known to have "fair" reflectors, you can extrapolate a best guess using this resource (3rd chart probably):

http://www.plantedtank.net/forums/showthread.php?p=1038305#post1038305

 

[J.Mcpeak]

"a nods as good as a wink to a blind man"
Distance is a factor as is number of bulbs and reflectors will increase intensity, agreed.
Many factors come into play including turbidity and surface agitation.
This can only be taken into account by some kind of light meter.

 

[Mijo51380]

Just want to save the link

 

[Lady_Alia]

This is gonna make me sound stupid but what is par?

 

[Brian_Nano12g]

Photosynthetically Active Radiation

 

[aqua_chem]

It's essentially a quantitative measure of light derived from counting photons in the range of light that plants can utilize.

 

[Lady_Alia]

It's essentially a quantitative measure of light derived from counting photons in the range of light that plants can utilize.

Awesome! Thanks for the explanation.

 

[J.Mcpeak]

May help, may not!

KELVIN LUX LUMENS PAR PUR