Actnic is ok but 2500-3500k are ideal as well as 650nm red leds! but no matter what light a long cycle 12+ as said above will promote no matter what!
I'd go with the leds so you can spot aim them at your targeted places so your whole tank isn't consumed. Or take the desired rocks out throw em in a Rubbermaid fill with water, throw in bubbler under each rock and keep a light on em 18 hours. The air and long light cycles will promote fast algae growth, add some fish food as well to feed the algae. If you decide to use 2500-3000k bulbs use cfl, easily buy them at your hardware store with a cheap 8$ clamp on utility light.
Same concept goes into my DIY algae scrubbers. A strong led 2500k light, 24 hour light cycle, rough plastic grid and a lot of bubbles. This grows algae where I want and not in the tank aka nuisance algae!
After a week:
All that crud would literally have grown on my plants, sub and tank! Meaning I have a problem somewhere helping algae thrive, probably high lighting but in any case I can keep it off my plants and everything grows like crazy!
Sorry for the blabber, just explaining the method I use to grow algae cuz I've done a lot of research on the matter! Hope some of it helped!
×Go S. Vettel #1 Infiniti Redbull! 4x WDC!!! Congrats on another flawless title and 9 wins back to back in 1 season (record!) See you next year in Australia boys!×
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Cheap way to decrease nitrates and keep your fish healthy:
http://monsterfishkeepers.com/forums/showthread.php?t=504763 
