Just as a point of reference in terms of efficiency
The 400 watt MH puts out 29000 lumens which is 72.5 lumens per watt
That 27 watt CFL puts out 1400 lumens which is 51.8 lumens per watt
The 5600 was the color temp in Kelvins not lumens
But florescent tech has been getting cheaper, more living space friendly, and more efficient with the intro of T5. You should consider a twin 24w 2ft T5 tube fixture as it will put out more then twice the lumens over a wider area of your tray. Home Depot has Lithonia Lighting Mini Strip 2-Light Utility Light that comes with ballast and 2 foot T5 bulbs for $25 bucks. You have to wire up your own the cord FYI. You can then upgrade to horticultural full spectrum bulbs when your ready. Home depot sells single cool white T5 replacement bulbs for $10, but for $52 you can get Sunleaves VitaLUME Grow Tube T5 2' 4 Pack, so like $12.80 a bulb. I use this type of setup as an under the counter light for our kitchen sprouter.
At 24 watt they each put out 1800 lumens at a 6,500K color temp.
75 lumens per watt!
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