Okay.
Your pH is too low.
You're using a completely wrong fertilizer for young cannabis, ESPECIALLY in hydroponics.
You have no way to check temperature.
You don't know your ppm- even worse because your fert is wrong to begin with.

You will either need to basically re-do your setup from scratch, following the basic DWC guidelines outlined in several grow logs (check the 'styles' thread stickied in basic), or consider switching to soil, which is more forgiving if you don't have the correct equipment.
stinkyattic Reviewed by stinkyattic on . revanche's dwc problem Im getting the same problem! sorry they are out of order: 1st pic: after a few days of spotting 2nd pic: after a week or so of spotting, they dry up and shrivel 3rd pic: early spotting, 1st day or so 4th pic: everything my setup: Rating: 5