what kind of water, what nutes. how much of each. need more info... likes like a slight deficiency of some kind, but as long as it doesnt get worse ur fine, but it could get worse...
check the ph after u add ur nutes... if u can also check the ph of the water that drains out the bottom of ur pot... nutes can drop or raise a ph of water just as much as ph up or down can. if its greater than 6.8 or less than 5.9 thats ur answer. and this is a very common problem among new growers. i myself ran into this until i got a good ph tester for $70,
i always test the ph after i add nutes to water and thats the price of my tester probably similar,can this happen after alot of stress couse they where in a toxic growbox for 2 months and i couldnt figure out what was the problem till i found this article on icmag that had the same problem as i, after i dismanteled the growbox they recovered beautifuly ,so could this be the couse of these pale colors