The problem is probably the Potassium or the Magnesium in your PMDD-mix that inhibit Calcium-uptake/usage. Curly leaves is a sign of Calcium-deficiency.
You get 4.42 ppm of K from the KNO3-dosage (7 ppm of NO3 from KNO3 yields 4.42 ppm of K) and also 23.7 ppm of K from the K2SO4-dosage.
That means 28.12 ppm of K which is quite some K.
http://fins.actwin.com/aquatic-plants/month.200401/msg00583.html
You get 4.42 ppm of K from the KNO3-dosage (7 ppm of NO3 from KNO3 yields 4.42 ppm of K) and also 23.7 ppm of K from the K2SO4-dosage.
That means 28.12 ppm of K which is quite some K.
http://fins.actwin.com/aquatic-plants/month.200401/msg00583.html