I'm currently retrofitting an old hood for some new LEDs. I wasn't really interested in anything other than genuine Cree XM-L2, so spent a little time digging around for ideas and components to make sure I was getting the best value:-
20volt/90Watt laptop power supply - £2 (ebay second hand)
10 * Cree XM-L2 cool white LEDs on stars - £35 (ebay - search for 'ledbloke')
10 * LED star heat sinks - £27 (Farnell -
http://uk.farnell.com/ohmite/sa-led-113e/heatsink-led-12-7mm-black/dp/2097677?CMP=i-bf9f-00001000)
2 * LDD-1000H LED drivers and board - £20 (from Coralux in USA)
Thermal paste/wires/screws - £10
So £100 or so gives you the guts of a well spec'd LED system with what are notionally the most efficient LEDs available atm. I'm setting it up to run the led's at 1000ma which should generate something in the region of 4100-4600 lumens for about 30watts of power.
I don't currently need anything else for the retrofit and I'll dim them via my raspberry pi.
I'm quite sure this is serious overkill for a 60*30 tank though. You could probably reduce the number of LEDs and maybe lower the cost even further with a couple of larger, individual heatsinks (such as
http://uk.rs-online.com/web/p/heatsinks/1898628/) for a slightly different approach.
The main attraction (other than cost!) for me, however, is the flexibility. At some point I'll transfer the led's to a home grown luminaire over a new, larger tank. All of the components are re-useable - I may need to add some additional drivers, or swap in a different power supply, or change the drivers and run them at a different current but the bulk of that £100 won't be wasted. Plenty of options if you're happy playing with electrickery and do a little research on how to set them up (pretty straightforward these days).
No doubt someone will be along shortly to burst my bubble
🙂 - but so far the build is working out pretty well.
Cheers, Mark