New to this and need help see pics

I am using a 600 watt hps and a 400 w hps the plants are in 5 gall containers and are about 4.5 feet tall. the medium is coco canna and i am using the coco canna nutrient A and B about 3/4 strength . Ph is always around 6.0, using rain water. in week 6 of flowering and I am giving them nutes every third watering. the n-p-k of A and b is 5-4-3 and i was tol to use this throughout the grow. I have also been adding a bloom agent called bloombastic and the n-p-k of that is 0-21-20. The Canna nute calls for 15ml per gal and ive been mixing it 10 ml per gal and the bloombastic calls for 2-4ml per gal and Ive mixed 2ml per gal on the last two feedings. I only water them every 3 days, the temp is 78-80 with lights on and 72-75 with lights off humidity stays around 63%. My problem is that my leaves a looking like an egal claw at the top of the plant and the plant has all purple stems. the leaves also seam hard and brittle. Any advise would be helpful if you need more info or pics just ask.