How much light for chaeto?

I had gotten a decent chunk of chaeto awhile back and couldnt decide where to put it at. I had a mesh bag so I just put it in there and attached it to the top of the tank. It has since almost doubled in size so I have been thinking of moving it to my sump. I have a 9"3" window in the top of my sump. I thought about putting a full length light under the stand but didnt want the extra light where I dont want it. With that size window what kind of light would I need to keep it growing? I have 2 led strips that you would mount under your cabinet. 15 leds each, they are on the yellow side, would those work at all?

 

Thanks Ill have to get one of those. I put my chaeto back in another bag for now. The bag was getting alot of unwanted algae growing on it, one reason I wanted to move it. But had grown out of the bag so much I had to cut the bag down the side and toss it.