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Re: [APD] light and the w/gal rule



well, i guess in my reasoning it would be the following. My 
understanding is that 30 ppm co2 is about the ceiling where it does any 
good. at least as far as research has gone. and that we've got the 
fertilizing to where we can fine tune it. so lets see how much light we 
can give them before it stops mattering. not everyone wants this but i 
wouldnt mind pruning several tanks daily. making cuttings etc. if they 
would grow that fast. especially hard to get plants. and then distribute 
them for shipping or locally at clubs. to be honest i have the tank 
disease like most everyone, but i'm at a point where i still want my 
tanks, but i'd like to farm to be honest, and other than that i guess i 
just want to know. hehehe, for knowing. i cant seem to muster any better 
explanation than that.
ian

S. Hieber wrote:

>The wpg recs are generally only offered for high flos and
>MHs, which have roughly the same efficiency.
>
>Wpg is a hand wave. It's a simple rough and ready way to
>hit a target that's a mile wide. You don't need a
>telescopic sight to hit a barn door. They wouldn't hurt but
>they aren't readily available to most folks, who luckily
>don't really need them.
>
>It's not that a person can't find out a lot more info than
>is readily available and then with some work, apply it to
>what bulbs they put on their aquarium. But in the long run
>I think a person would be hard pressed to show that their
>tanks grew better than others' and the reason was the bulbs
>that are x% stronger than those the others use.
>
>How much light do you need on your porch? About 15 watts
>fluorescent or about 40-60 incandescent.  Could a finer
>prescription be develooped? Sure. Would we have better
>porches? Generally not, imo.
>
>sh
>
>sh
>
>
>
>--- urville <urville at peoplepc_com> wrote:
>
>  
>
>>thats what my other post was about.  watts is just not
>>the way to go. 
>>not all watts are equal is what i'm saying. bulb
>>effciency is a big part 
>>of it and as wright was pointing out to me that includes
>>wasted light in 
>>the infrared and non useable uv spectrums. the numbers
>>all around just 
>>arent for our use and i think till this point there wasnt
>>a need for 
>>them, unless the exsist in some science journal
>>somewhere.
>>
>>Jerry Baker wrote:
>>
>>    
>>
>>>S. Hieber wrote:
>>> 
>>>
>>>      
>>>
>>>>Well, if you want to go whole hog, use Pearson's R to
>>>>        
>>>>
>>do a
>>    
>>
>>>>partial regression on all the relevent factors, and
>>>>        
>>>>
>>don't
>>    
>>
>>>>forget to take into account the spectral shift that
>>>>        
>>>>
>>occurs
>>    
>>
>>>>with age and variations that occur coming off the
>>>>production line, etc. When you're all done, most folks
>>>>        
>>>>
>>will
>>    
>>
>>>>find that they wpg still works well, is close at hand
>>>>        
>>>>
>>and
>>    
>>
>>>>convenient, and works as anything else. It's not like
>>>>        
>>>>
>>there
>>    
>>
>>>>is some critical value of light that has to be obtained
>>>>        
>>>>
>>or
>>    
>>
>>>>else plants won't grow well. 
>>>>   
>>>>
>>>>        
>>>>
>>>There is such a value, but it's probably different for
>>>      
>>>
>>individual plant 
>>    
>>
>>>species and aquarium conditions.
>>>
>>>One neat thing about regression analysis is that it
>>>      
>>>
>>doesn't matter *why* 
>>    
>>
>>>something is correlated, it just is or isn't. I can
>>>      
>>>
>>explain 96% of the 
>>    
>>
>>>PAR output using lumen data alone, and I will be within
>>>      
>>>
>>3.5 PAR of the 
>>    
>>
>>>true PAR value 89% of the time. That's pretty good to
>>>      
>>>
>>me. It doesn't 
>>    
>>
>>>really motivate me to go find the source of that other
>>>      
>>>
>>4%.
>>    
>>
>>>Your suggestion gave me an idea. Since lumens are based
>>>      
>>>
>>upon almost the 
>>    
>>
>>>same spectrum of light that PAR is, but uses a weighted
>>>      
>>>
>>curve of 
>>    
>>
>>>perceived brightness as seen by the human eye, I
>>>      
>>>
>>wondered if lumens and 
>>    
>>
>>>watts taken together would make a more accurate
>>>      
>>>
>>predictor of PAR than 
>>    
>>
>>>lumens alone. Thank you for the idea. I now have a
>>>      
>>>
>>logarithmic equation 
>>    
>>
>>>with an r-squared of 0.98!!! Here's the equation:
>>>
>>>PAR = 0.13 x sqrt(lumens x watts)
>>>
>>>So, for an example let's use an AH Supply 55W bulb. We
>>>      
>>>
>>know it's 55 
>>    
>>
>>>watts and has about 4700 lumens. That comes out to a PAR
>>>      
>>>
>>of 66. Who 
>>    
>>
>>>knows how true this is?
>>>
>>> 
>>>
>>>      
>>>
>>_______________________________________________
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>>Aquatic-Plants at actwin_com
>>http://www.actwin.com/mailman/listinfo/aquatic-plants
>>
>>    
>>
>
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>  
>
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