Switched nutrients having a problem

Switched to front row ag and powerSI plants aren’t looking the so great. PPMs were over 1,000 so I dialed them back. Was following their feeding schedule but I think it’s too high. I’m down in the 4/500s. Now I’m wondering if it’s a cal/mag deficiency. Half the plants have purple stems. Front row claims you don’t need cal/mag. I’m just not liking what I’m seeing.
3 gallon fabric pots , canna coco, RO water and hand feed for the time being

You're on the right track. The first two pictures do show cal-mag issues. Especially the slight curled edge of leaves. The bunched stunted tips in the second pic leans to phosphorus.
Water. Its the issue likely. Whats the pH? Coco is finicky with calcium and magnesium might need more of that. But is there good air circulation? The curled leaf edge could be a symptom of not moving water and electrolytes through the plant. Evaporation, through wind helps this out.

Up the feed, get back around 1000 PPM.