EDIT
I really butchered this final draft.
The post was supposed to be a lot less vitriol.
I've been trying to cram the most info with the least words. Sometimes it doesn't sound right.
I'm going to take the winter off from bananas and write some tutorials on a couple subjects on which I can speak authoritatively. Some of the info here is lacking or scattered.
Hope this post didn't turn anyone off.
Quote:
Originally Posted by jmoore
I think I'm having de ja vu...isn't this where Richard gives his sage like advice...
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at the risk of sounding like a jerk
maybe Richard got tired of teaching + and - in his calculus class
This will be my final post on lights until I find a way to distill this complex subject. Maybe I'll make a ULTIMATE GUIDE post and just permalink.
it has become clear that people understand neither lumens per watt nor watts consumed
this is really simple math
if both lights A and B consume the same watts,
if light A makes 95 LPW and light B makes 105 LPW then light B is clearly more efficient and light A probably making more heat
simple
go to the local electrical store and buy
150HPS ballast $23
150HPS universal mounting bulb MEDIUM base $5-10
medium base socket $3
can you get a T5 for $35? NO
be sure to put those T5 light within a foot of the leaves.
this may be too complicated
Inverse-square law - Wikipedia, the free encyclopedia
this is better
Rules for Perfect Lighting: Understanding The Inverse-Square Law
here is the meat
According to the law, the power of the light will be inversely proportional to the square of the distance. So if we take a distance of 2 and square it, we get 4, the inverse of which would be 1/4 or rather, a quarter of the original power – not half.
LIGHT INTENSITY AT 2FT IS 1/4 LIGHT INTENSITY AT 1FT
you must have these flouros nearly touching or you are wasting time and money PERIOD
HPS is more forgiving as a point source inside a cone reflector (but does not circumvent this law)
good luck with your lights