it looks like it is being over watered to me maybe a little of a nitro diff due to the yellowing of the oder and bottom leaves. but yes as stated before foil is a horrible thing to put up in a set up it does create hop spot on the leaves which can in turn kill the plant. also what kind of nutrients are you using, and also why ar u using a 12/12 if you are in veg stage you should be running more like a 18/6 light cycle.