I have noticed on some of my orchids, new growth turning black. From pictures I see, this indicated a cal deficiency. I have only used it 2 times so far. My question is, do I use it for every watering? ( somtimes 2 or 3 times a week)Also is there any orchid you would not use it on.? I also sometimes use some raw seaweed. Can I mix this all together?: