dont add anything to your soil! i honestly dont think its a deficiency. you have been veggin for almost 4 1/2 months now from the looks of your first post. to me i think its going into lockout from too much salts in the soil. also the soil will tend to get acidic if you veg for that long cause the soil gets beaten up and the ph buffers will break down. check your ph run-off and get back to us. it wouldnt hurt to do a proper flush and water with half strength nutes. but check that run-off first and fill out the troubleshooters form!