Lumens vs. lumenseconds

I have a couple of octacool-9 fluorescent lights made by Impact. I was quite surprised by the lack of light I get from them. When I photograph kids in my small in-home studio, I typically need to shoot at 800 iso in order to get a high enough shutter speed to stop their quick movements. B&H says that each light puts out 12,600 lumens. I was looking at the alien bee 800's and it says they have 14,000 lumenseconds. These numbers seem pretty close, but i am pretty sure the alien bees aee more powerful and would allow me to shoot at a lower iso.   It there a difference between lumens and lumenseconds? Trying to understand why these seemingly bright lights are not allowing me to shoot at a lower iso?