I considered building my own LED unit but after research decided it was hardly worth the effort in truth after I found others are using these off eBay.
http://www.ebay.co.uk/itm/2217088853...%3AMEBIDX%3AITMy
leaflet box scrubber immediately after installation and prior to installing my LED units.
My screen size is 6" wide by 7" long.
One of mine mounted on my DIY supporting rig.
The two mounted on my sump in front and beghind of my leaflet scrubber. Skimmer cup removed to get a better shot of it.
A 10w version is just $12 and the 20w $23 They come with the right 650/660nm LED's and a couple of 440/450 blues. They are also splash proof, come with heat sink slim casings, mounting brackets and can be adjusted into different angles.