If it was insects you'd know. This is going to be either pH related .... Which I don't see listed in your diary, or the beginning signs of a magnesium deficiency/lockout which could be happening because of your pH is off
Looks Good To Me. ^^
But leaves are useless storage in indoor grow and you could defoliate a bit next week to help the light reach the lower branches (let the soil dry a bit before doing because with less leaves, your plants should drink less).