Cree LED for discus tank: XPG-2 VS. XML-2

[ewanvt]

I am building a DIY LED setup for my 6 FT discus tank.

I have done some research and i think i will need either XML or XPG LED's

please give me some advise on what the recommended setup is for a freshwater led setup.
all input will be much appreciated.

as per the PAR calculator this is my breakup:

XML: XMLBWT-00-0000-0000U2051

Lumens per LED 580
LED Spacing (inches) 4.5
Number of LED rows 2
LED Height (inches) 30
Cone angle (degrees) 40
PAR= 86
planned fixture length (inches) 72
Total LED's needed (Per row) 16
Total LED's needed (For all rows) 32

OR

XPG: XpGBWT-L1-0000-00H51

Lumens per LED 458
LED Spacing (inches) 4
Number of LED rows 2
LED Height (inches) 30
Cone angle (degrees) 40
PAR= 86
planned fixture length (inches) 72
Total LED's needed (Per row) 18
Total LED's needed (For all rows) 36

sources:

http://www.plantedtank.net/forums/sh...d.php?t=168999

http://www.cree.com/~/media/Files/Cr.../XLampXML2.pdf

http://www.cutter.com.au/prodimages/...LIM%281%29.pdf