Originally Posted by Pisces3473
Lot's of good options there thanks for chiming in. I will look into both of those options. What is PAR? I'm just learning about the lights, please excuse my ignorance.
If I'm going to use LED
's then they need to be at least 3 watts each and cover the whole tank. And the blues are just for looks right? I should go with whites?
Here is a quick explaintion of PAR vs PUR I copy from a freshwater forum, but it pretty much sums it up very nicely.
Photosynthetically Available Radiation
(PAR) is defined as the amount of radiant energy available within the approximate spectral range of 350 to 750 nm (Tyler 1966). Instruments commonly used in studies of photosynthesis are PAR meters; that is, they report 400J700 I,h) or total PAR.
Photosynthetically Usable Radiation
(PUR) is defined as
the fraction of photosynthetically available radiant energy of such wavelengths that it can be absorbed by the algal and plant pigments(in this case, coral). Light is selectively absorbed by most algae in the blue and red regions of the
spectrum, causing the transmitted light to be concentrated in regions of the spectrum where algal pigment systems are ineffective at trapping light for photosynthesis (Sullivan et al. 1984). PUR is necessarily less than
PAR, and PUR will depend on both the pigment complement
of the microalgae and the spectral composition
of the available submersed radiant energy.
In general for reef tank,
(Acropora) require 200 ~ 550
(Montipora for example),Clam and LPS
150 ~ 250
Softies are 50~150
So let's say at 16" your PAR reading is around 150, that means at 16" deep, you can keep anything from soft coral to LPS
For pic and Nano tank, you don't have to get 3w LED
, as long as the LED
fixture provides the right spectrum and PAR then you are all set.
Blue is very important for your corals, only keeping white LED
will turn all your coral to brown because it is the wrong spectrum. Coral require somewhere between 380nm to 480nm spectrum to grow and be healthy, White LED
has mainly 500nm to 700nm, which promote brown algae growth