hey KD I was reading back and noticed you're using the promix... might be part of your prob... it has tons of peat in it and even though the pH is fixed, peat holds water a bit too much and can contribute to weird def symptoms, especially in cooler temps.
Next time try my favorite mix, 50% composted manure and humus, 40% perlite, and 10% worm castings. The worm castings are a new one on me but my grower friend swears byu them and I'm coming around. The key though is LOTS of perlite and NO peat moss.