I am using 3 CFL bulbs at 1500 lumens EACH BUT I will be changing them to bulbs which have 2275 Lumens EACH.

The results for the light intensity of my grow box:

Square Footage Under Light Source = 4 Square Feet
Formula: lumens/ft2

1500/4 = 375 x 3 = 1125 Lumens
2275/4 = 568.75 x 3 = 1706.25 Lumens

minimum of 2000 lumens/ft2, optimal 5000-7000 lumens/ft2.

So according to your formula i need 20,000 Lumens? Thats hell of a lot...