Can you post a pic of the whole plant in the ground. How tall is it, what percentage of leaves are crooked/curled. Are the bad leaves evenly spaced around the plant or do they occur in certain areas around the plant.
1. I'd learn to tell when your plant needs water and only water her when she needs it. Chances are she'll droop and new stems will soften up a little bit.
2. Growing outdoors in the ground really increases the variability of factors that can affect your plant. Your roots are exposed to a more heterogeneous soil.
3. Viruses are really common in plants and can cause a response that looks like leaf burn and curl.
4. No need to pH R.O. water. I'm not sure you're going to get an accurate pH reading of the water initially anyway as the ions in the water are low. Low ion water can screw up your pH meter over time also. Also what is your need for RO water, decent tap water is usually good if you let it air out for a couple days.
5. It would be good to know the conductivity or TDS of your R.O. water.
6. Aside from the leaf curl your new growth looks healthy, I don't think you're experiencing a nutrient problem.
7. What is the soil made of? Sandy, loamy, clay? Good particle content for drainage? Can you describe the drainage a little better. How many gallons of water do you use and how long does it take to disappear into the ground.
My last leaf curl problem was from over-watering and pH adjustments. I do like the idea of using CaMg in you water but low concentrations if your going to use it every watering. Also probably no need to pH down your water with growing outdoors and using the fox farm, like the other dude said.
You may want to consider covering the top few inches of ground above your plant with some mulch. Then add the fox farm, then water. When you water use a shower type spray don't just let the hose run into the ground. The FF is some decent food but it may be burning your top layer of roots and tricking out your leaves. The mulch will help to disperse and dillute the FF before it gets to the root base. You might have got a little short term shock from the initial dose of ferts.
Definitely if you added the FF and then added something else a week later you could have some localized hot spots in your root bed causing problems with your new growth.
From what i see you've got a minor problem with the leaf curl but she'll probably do well in the long run.
Less is more baby. Keep the Zen.