Organic Purple Romulan

Getting into Veg now, 1,2,3,5 all showing 2nd set of true leaves, 4 is looking a little deformed, and not growing as fast as her sisters. Switched to a 650w blurple, planning on upgrading this light again to a sun-like, full spectrum LED setup before flowering. Noticed all of the plants have purple stems, could be genetics or a mag/Phosphorus deficiency. Also noticed the leaves are quite waxy, particularly #3 (thinking this could be a different pheno?) Again could be genetics or possibly over feeding.. Going to cut out the marphyll this week, and just water with pure R/O water, will see if this makes a difference.