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Watts/lumens (again?)
Okay, guys, help me out here. When we talk about two watts per gallon, are we
talking standard florescents? By standard I mean those 3180 lumens 40 watt
tubes that come standard on most light fixtures and are sold in grocery store
everywhere. They offer 79 lumens per watt, or thereabouts. So if I for
example put two of these over a 40 gallon tank I have two watts per gallon, or
about 158 lumens per gallon. But re we talking two 40-watt bulbs without
decent reflectors? Or are we talking about light fixture with a reflectivity
of 50%. Or are we required to get something like "Coilzak", which has an 89%
reflectivity minimum guarantee? If I use a highly reflective fixture, can I
say that I have inceased those 158 lumens by 90%, because all the light that
was going up instead of down is now heading properly into the tank? Which
would put me at 300 lumens per gallon.
And then what happens when we go to the local lighting store and find Philips
ultralumes, which are visibly way brighter than standard bulbs? Or are we
already talking about the enhanced output bulbs when we say that we have two
watts per gallon?
Okay, I know that this is just a rule of thumb to simplify our tank planning
and layout. Yet I read numerous discussions here about alkalinity, pH,
ferrous compounds, EDTA, etc. ad infinitum which seem to get really really
detailed, certainly more detailed than most of us need to get a handle on the
basics. Now I want some more guidelines. I have three tritons over my 30
gallon tank. They look twice as bright as the bulbs that came with the strip
lights, so do they count as 60 watts each? I am setting up my 55 to have one
F40/T12-75UL, one F40/T10-50AX, and two Interpet Triton 40 watters. All of
these bulbs are way brighter than the standard F40/T12 bulbs. Am I overkilling
it? And do you know of a website for Philips or Interpet where the lumens
ratings for these bulbs are posted? Or an address I can write to?
Bob Dixon