Quote:
Originally posted by DJ88:
I just measured the lumen output of three 95W VHO Actinics and it barely put out 3000 lumens at 4". As well the PAR of those three is only 100. Not a lot is it.
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<font size="2" face="Verdana, Helvetica, sans-serif">was that 4" in air Darren? and were they old bulbs? that seams very low especialy at 4". at 24" I am getting a PAR reading of 156 with two 96 watt PC's (one new 10000K and one 5 or 6 month old 6500K) I know PC's are more intence than VHO but I didn't think it was that it would be that much of a difference. If I turn on my 3, 30 watt NO actinic bulbs my PAR jumps to 180.
So, to re-enforce what Darren had said yes actinic lighting does make a difference but it is small, and definatly cannot be compared to full spectrum lighting
Quote:
Originally posted by reefburnaby:
Some PAR sensors are off by as much as 50% in the blue spectrum.
Victor.
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<font size="2" face="Verdana, Helvetica, sans-serif">Hey Victor, the PAR sensors Darren and I have UNDERSTATE the amount of energy in the lower part of the PAR range, but it overstates the higher end of the PAR range. when it is ballanced out ir is a fairly accurate repensentation of the total average amount of PAR (380nm to 700nm).
Now, one thing I must say is that "watts/gallon" means absolutly *{squat}* and is a horable way to compare lighting. what counts is the intensity at a specific point in your tank. now to show why watts/gal is useless lets say you want to obtain a PAR reading of 275 at the bottom of a 24"x 24" x 24" (60gal) tank well one 200 watt Iwasaki would be there (I think) but you could have 8, 75 watt VHO bulbs on your tank and never get that high of a reading. so the MH route has a total of 4.1 watt/gal whare the VHO tank has a rating of 10 watt/gal but never comes close to the amount of light the MH tank has.
Steve
[ 20 May 2002, 13:13: Message edited by: StirCrazy ]