Wattage or Spectrums?

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Esoteric Backbone

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I was told that it doesn't matter so much about how much wattage you use for your plants, but what type of spectrums they give off. Is this true at all?
 
Both are important!

Depends on your tank size, what plants you want to grow, what inhabitants you have already etc etc....

I've been reading around on these forums a bit, and from the looks of it keeping plants growing happily and healthily is arguably harder than fish! Especially for the really high light plants!

Generally speaking you would want a daylight spectrum light source. IE the bulb or LED or whatever you use has a colour temperature of 6500K or above.

Like I mentioned the wattage will depend on tank size and whether you're looking for low, low-mid, mid, mid-high, or high light...

1-2 wpg (Watts per gallon) is a rule of thumb often used for the low/low-mid starting point.

But also worth considering is the light intensity... IE if you had a 50W T5 and a 50W T8, the T5 would be more intense as it's producing a the same amount of light as the T8 but from a smaller external surface area.

I'm no expert, I wouldn't even say I was semi-experienced. I'm a novice and what I've learnt so far comes from trawling these (and other) forums!

So in short, yes and no. :D

HTH
 
L.U.X is important, that is the strenght of the light! 20 watts sun glo from hagen is a low source of light compare to the lifeglo 20 watts from hagen to! The best is all 3, a high L.U.X, the IRC at 98% plus a good spectrum, if two bulb choose two diff light to have a better spectrum. Add a good wattage for your need( aquarium and plants) is important to!

Plants are more complicated than fish!
 
The metrics you're really looking for are PAR (photosynthetically active radiation) and PUR (photosynthetically useable radiation). Unfortunately measuring these quantities requires sophisticated (read expensive) equipment. This link has more information than you probably want, but it's good stuff: Aquarium Lighting; Kelvin, Nanometers, PAR, Bulb, Watt, MH, LED, Light Basics.

Since most people don't have a PAR meter, we attempt to substitute wattage and spectrum to get some basic guidelines. As long as you're using a bulb in the "white" category, wattage is more important than spectrum. That said, a bulb that puts out a lot of reds and blues will work better than a bulb that puts out a lot of yellows and greens.
 
Focusing on either alone is gross over-simplification. Plenty of "watts", but totally wrong spectrum, you won't do your plants any favors- just as the correct spectrum, but not enough wattage also won't help.
 
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