So is this just perlite grow, like hydro? Switch to potting soil. Are you actually using a fert at all? silica and superthrive are fine to use in real small amounts, but you need to fert too. Chances are good if you just switch to potting soil and not do much else, you'll be okay. You can put in some powder fert which will stabilize the fert use. Mix it in the soil. It looks like you're growing in a real shallow level with no fert. I'd stop the misting because it's not necessary and if there is fert in the mix, this can be a problem because it seems like this kind of plant doesn't respond well to foliar feeding. Grow it more like you would a house plant. The more fancy you get, the more trouble happens.