I'm using all rocks mid size for this plant in plastic pot. NKCa same ratio. Im feeding up to 100 ppm when warm and light is long. The plant seems okay and it has two new growth while flowering. What is interesting is that the yellow/brown tips slowly disappeared and I thought it was from the salt. I go out of the box all the time. If they die,,, then i have now a good reason to buy. Hehe,,, dont follow me.