The new growth on those looks good- Some scarring and deficiencies on low leaves is to be expected with clones; the leaves that were on the cutting when it was taken always seem to fall off or end up looking scruffy. It's only when you don't get vigorous, healthy new growth that you should really be worried. Your conditions sound good and look good. If you didn't pre-soak your clay rox to set the pH before adding plants, you'll want to keep an eye on them and adjust the res pH frequently until it is stable, but things look good up in thurrrrr.
The light green leaves in the middle of the plant, if they don't improve, are worrisome though. Would you mind posting a closer pic of the worst affected plant- the whole plant, showing the top view and a sort of diagonal side view showing both upper and lower growth?
Edit: You are using calmag right?