3 plants, same age, low thc?

Ok i got 3 plants (Suppposibly White Widow) using the same reservoir and all 3 plants are in the 8th week of flowering and one plant must have 2 to 3 times the trichomes as the others and has all clear trichomes and no gold hairs yet even forming. The wierd thing is the 2 smaller plants pistals are beginning to turn the goldish brown and I took a look at the trichomes close up and they are mostly the cloudy tri, no brown or gold yet. So any thoughts