My led set up is different Ludnix, Im using 10 3 watt leds, over a 15"x10"x8" tank (its the test pico, i have twin 250's over the 4ft marine)
And i have 5 Cree X-RE Royal blues and 5 Cree X-RE "R2" (whites), each string is regulated by a luxdrive BuckPuck (Each buck puck has a pot on it to dim the lights, but you can snip this off and supply a PWM signal to dim them) if you were desperate, you could wire up to 1-18(maybe a few more) 1 Watt led's to a buck puck and just supply a PWM signal if you cant get any further. but i bet you could wire them up and power them off an Arduino, even if they require 6 v , you could ether drop a few leds or use transistor (think thats the one) to beef up the voltage, failing that you could always salvage the Led's out of it, heat shrink them and just create a new 5V chain.
got my jump leads, and my Temperature probes in the post today, the RTC coding is giving me a bit of a head ache so i mgiht try and work on the Temp chips now they are here.
i desperately need to order some new bread boards but i cant bring myself to buy one of those large 2.5K point boards (like oyu have) that £20 could go to a complete new module/component 