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Murfman
04-23-2012, 11:44 AM
http://www.bostonreefers.org/forums/showthread.php?117895-The-PAR-Estimation-examined-Lighting-Spectrum-and-HEV-thread

SpaceOps
04-25-2012, 09:29 PM
Measure PAR for blue wavelengths independently, then multiply the PAR reading by the corresponding multiplier below to get the actual PAR.








Wavelength



Multiply the Apogee reading by



400



3.3





410



2.5





420



2





430



1.6





440



1.4





450



1.25





460



1.2





470



1.1





480



1.1

Pride of the rockies
04-26-2012, 01:36 AM
So I recently had my PAR readings taken on my tank, 24x24x24 60g cube powered by an Ice Cap HQI ballast and Radium 20000k bulb sitting one foot above the tank in a LumenMax3 reflector. I was getting 250 on the sandbed, 300 midway and 600 just below the surface. According to the data, I should add 23% for light loss? So my numbers are really 307, 369, and 738 respectively! No wonder sticks hate me.

Murfman
04-26-2012, 06:11 AM
So I recently had my PAR readings taken on my tank, 24x24x24 60g cube powered by an Ice Cap HQI ballast and Radium 20000k bulb sitting one foot above the tank in a LumenMax3 reflector. I was getting 250 on the sandbed, 300 midway and 600 just below the surface. According to the data, I should add 23% for light loss? So my numbers are really 307, 369, and 738 respectively! No wonder sticks hate me.

What was the wattage on the HQI ballast? I was getting 1300 at the surface under my 400W Moguls at 12K

SpaceOps
04-26-2012, 10:58 AM
Were you using the Apogee or Li-Cor quantum meter?

The Apogee conversion factors don't work with lights that aren't monochromatic. Your halides, while spiking in the blue region, are also putting out light in the region where the Apogee is fairly accurate.

Pride of the rockies
04-27-2012, 02:45 AM
250w. The bigger question is, how high do they need to be in order for me to stop cooking coral?
I should note that those numbers where under the reflector, on the sides I got a consistent 175 from top to bottom.
I believe it was an apogee sensor

Murfman
04-27-2012, 05:30 AM
Here are my readings from Jan of 10. This was with the MH and new bulbs; http://i107.photobucket.com/albums/m308/Co_murfman/Par%20Readings/Jan10Parreadings.jpg

You would want them high enough so that you get numbers in the 400s at the coral. You might have to move them down or put screen layers between the light and corals and weekly remove a layer.

Pride of the rockies
04-28-2012, 01:48 AM
400's you say...ok, I'll believe that. Besides, it makes the proposed canopy shorter :)

Murfman
04-28-2012, 08:38 AM
Thread on par readings, on my tank, start here; http://www.thescmas.com/forums/showthread.php?2380-Murfman-s-300-Acrylic-with-bar&p=80117&highlight=readings#post80117