I’m kind of bored of those old school florescent lights, and want to challenge myself to build a light, honestly i have no knowledge at all, so please bare with me, i have a 30” florescent light canopy, i want to strip it off and put 6 led in, i would like a combination of 4 cool white and 2 pink-ish if they’re available. I don’t need it to be super bright because it might scare my fish, so medium is good. So, where do i purchase the LED? what else do i need? powersupply, wires, etc… would prefer to have an on/off button as well. any tips will be great appreciated! i have those 3m LED strips lights, i tried to connect it with a 12v power adapter and plug it into the wall but it doesn’t turn on, what am i missing? also by the look of those strip lights i don’t think it’s bright enough, plus i don’t like the blue mixture in there. this is a fresh water tank so white and some pink would be perfect, for my flowerhorn. 
Probably the best thread covering the subject that I have yet found online is this one. It covers build strategy, materials, color rendition, heat sinking the emitters and balancing the emitter strings for vF. Enjoy!
What kind of fish do you have? Assume no live plants?
I can’t really help, but I used to have some nice planted freshwater tanks, mostly with smaller schooling fish. My solution was two 36in T5 high output flourescents. I bought complete fixtures with bulbs and reflectors from one of those hydroponics stores for like $40ea. At first I went even cheaper without the reflectors and used a dollar store foldable windshield sunshade, which was fine, but the proper reflectors look better and are more efficient for light penetration. I used some nicer wire shelving from Home Depot as my tank stand, (with proper modification,) so it was easy to hang the lights from above.
Anyway, sorry for the ramble, but I’ve been thinking about starting a tank up again and I hope you get some good responses.
So, would you be happy if you had LED strips that worked? You say they didn’t come on? Do you have strips, controller and power supply? Or just strip & power supply? You need a controller and a 12 volt 1 amp wall wart power supply & a way to adjust the controller. Its usually a IR remote. Then it should work just fine. 1 amp should be plenty to power two 3 meter strips. They should be pretty bright if packaged in the hood with the reflector. I would also put a white or light blue back drop on the tank.
The strips I have would make a tank rock and I would have unlimited color choices. Look up SMD 5050 strips. I would suggest getting a 2 amp supply to make sure they are super bright! And not all 5050 Leds are the same. The cheaper Chinese ones work, but there are better quality out there.
Here are Some links to give you a idea. The cheap controller works ok. I would suggest a higher quality but this is to give you a idea.
Check out these: http://www.superbrightleds.com/moreinfo/rgb-bars-and-strips/nfls-rgbx2-series-high-power-rgb-led-flexible-light-strips/1470/
Are you after a light with a natural purpose or decoration for the tank?
What is the size of your tank?
Fresh or Saltwater?
If fresh, Ciclids?
What type of filter are you using?
Live plants or Coral?