yellow leaves/pics

hey so recently i moved my plants closer to my lights and the plants have been showing signs of rapid growth since ive done so just one of the leafs on the bottom of the plant has began to turn yellow can anyone tell me what this is problem could or couldnt be?
 

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hey so recently i moved my plants closer to my lights and the plants have been showing signs of rapid growth since ive done so just one of the leafs on the bottom of the plant has began to turn yellow can anyone tell me what this is problem could or couldnt be?

and not to mention the tips of one of leafs higher up on the plant has began to curl up towards the light and these are the only 2 leafs on all 3 plants that are havin problems
 
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