Ive been getting like black blotches on my plants. I have amazon swords, anubias nana 'petite', an ozelot sword and a baby tears. My plants are becoming very very delicate too. They are getting to the point if you touch the tips they will break off. They get around 10-12 hours of 1.6 wpg a day. My parameters are very nice. 0-0-20. I use 3 caps full of Kent freshwater plant and 3 caps full of Kents Plant Pro every two days. Anyone know whats up?