Here's a link to a thread at CW where this guy tested several brands of HPS lights with a light meter. Very interesting results.
http://www.cannabisworld.org/vbport...php?s=&threadid=71441&perpage=15&pagenumber=1
all credit goes to ceteris paribus, here are some of the tidbits I found interesting:
these were some of the results:
i'll check tomorrow AM. 5000 ft candles is half the intensity of full sun, and fwiw, according to my cheapo hydrofarm light meter manual, the maximum amount utilized by plants. 5000ft candles converts to 53.8 Klux. i just so happened to take my measurements this morning at 20" from the lamp. none of them came close to 53.8 Klux.
test specs:
ballast and reflector from P.L. Lighting Systems
hanna high intensity digital light meter, measuring up to 200 Klux
each reading was taken after 15 minutes. readings level out after about 10 minutes. side lighting accounted for approx 2 Klux of each reading.
results:
sylvania grolux 34.0
agrosun 33.2
philips son-t green power 31.0
plantastar 30.1
agromax #1 (3 weeks old) 25.4
agromax #2 (3 weeks old) 24.0
son-t #1 (1 year old) 33.2
son-t #2 (1 year old) 32.0
son-t #3 (1 year old) 26.1
This guy was using a PL aluminum reflector and found that when the aluminum insert was removed his Klux increased!!!! It's on page 2.
"HR, results are going to vary according to the reflector used. i did as you suggested, using the P.L. aluminum reflector, and found these readings from a distance of 17" from the underside of the lamp:
base: 41.4
middle: 53
an inch past middle (maximum reading): 55.1
tip: 50
but here's where it gets interesting...i moved the meter back to the sweet spot and then took the aluminum reflector out of the hood, and the intensity went up to 69.4! WOW!! remove the expensive, heat reflecting aluminum, and get a 26% increase in intensity. less heat, more light...things are looking up. the gains weren't just in the sweet spot, either. the lamp base reading increased by 25%, and the tip reading by 20%. i didn't have time to grid the footprint, i'll get to that later. i have another reflector to experiment with as well...more results to come."
He then modified the hood by painting the aluminum reflector with flat white paint from an auto store (the paint is used for engines so has high heat resistance) results are below:
if you go to NAPA and buy a can of flat white 1200F spray paint for $4.99, you can make a winner out of that aluminum reflector. after yesterday's 4 light coats of paint had a chance to dry, i installed the reflector again. here are the results of a spot test:
no reflector, just hood: 40.0
aluminum reflector: 32.6 (ouch!)
reflector, painted flat white: 41.6
we have a winner! at least for me, the aluminum/mylar/flat white debate is over. flat white wins hands down, or else my meter is telling me lies. all of my reflectors are being painted today.
Here's a reflector comparison by Tal:
http://www.cannabisworld.org/vbportal/forums/gallery.php?userid=9324&action=view&in=Tal-sTest.jpg
there's other interesting stuff if you wanna read through the rest.
Peace
PK
http://www.cannabisworld.org/vbport...php?s=&threadid=71441&perpage=15&pagenumber=1
all credit goes to ceteris paribus, here are some of the tidbits I found interesting:
these were some of the results:
i'll check tomorrow AM. 5000 ft candles is half the intensity of full sun, and fwiw, according to my cheapo hydrofarm light meter manual, the maximum amount utilized by plants. 5000ft candles converts to 53.8 Klux. i just so happened to take my measurements this morning at 20" from the lamp. none of them came close to 53.8 Klux.
test specs:
ballast and reflector from P.L. Lighting Systems
hanna high intensity digital light meter, measuring up to 200 Klux
each reading was taken after 15 minutes. readings level out after about 10 minutes. side lighting accounted for approx 2 Klux of each reading.
results:
sylvania grolux 34.0
agrosun 33.2
philips son-t green power 31.0
plantastar 30.1
agromax #1 (3 weeks old) 25.4
agromax #2 (3 weeks old) 24.0
son-t #1 (1 year old) 33.2
son-t #2 (1 year old) 32.0
son-t #3 (1 year old) 26.1
This guy was using a PL aluminum reflector and found that when the aluminum insert was removed his Klux increased!!!! It's on page 2.
"HR, results are going to vary according to the reflector used. i did as you suggested, using the P.L. aluminum reflector, and found these readings from a distance of 17" from the underside of the lamp:
base: 41.4
middle: 53
an inch past middle (maximum reading): 55.1
tip: 50
but here's where it gets interesting...i moved the meter back to the sweet spot and then took the aluminum reflector out of the hood, and the intensity went up to 69.4! WOW!! remove the expensive, heat reflecting aluminum, and get a 26% increase in intensity. less heat, more light...things are looking up. the gains weren't just in the sweet spot, either. the lamp base reading increased by 25%, and the tip reading by 20%. i didn't have time to grid the footprint, i'll get to that later. i have another reflector to experiment with as well...more results to come."
He then modified the hood by painting the aluminum reflector with flat white paint from an auto store (the paint is used for engines so has high heat resistance) results are below:
if you go to NAPA and buy a can of flat white 1200F spray paint for $4.99, you can make a winner out of that aluminum reflector. after yesterday's 4 light coats of paint had a chance to dry, i installed the reflector again. here are the results of a spot test:
no reflector, just hood: 40.0
aluminum reflector: 32.6 (ouch!)
reflector, painted flat white: 41.6
we have a winner! at least for me, the aluminum/mylar/flat white debate is over. flat white wins hands down, or else my meter is telling me lies. all of my reflectors are being painted today.
Here's a reflector comparison by Tal:
http://www.cannabisworld.org/vbportal/forums/gallery.php?userid=9324&action=view&in=Tal-sTest.jpg
there's other interesting stuff if you wanna read through the rest.
Peace
PK
